bluuebunny/crossref_metadata_2025 huggingface dataset:
Maternal effects on some biochemical characteristics of the blastocyst in the domestic rabbit
Authors: Hafez E. S. E. , Sugawara S.
Published: February 2005

Blastocysts from nulliparous, multiparous, superovulated, post‐partum, and lactating rabbits were recovered five to nine days post‐coitum (p. c.), weighed, and dissected in order to obtain the blastocoelic fluid for analysis of glucose, lactic acid, and nitrogen. The largest daily percentage of increase in the volume of blastocoelic fluid occurred between five to six days p. c., whereas, the largest absolute increase occurred between seven and eight days p. c. The weight of the blastocyst and trophoblast, and the volume of fluid was higher in the multiparous and post‐partum does than in others. At eight days p. c., the concentration of glucose in the blastocoelic fluid reached a maximum comparable to the maternal blood level; subsequently a decline occurred. Lactic acid levels were similar to those of glucose. The amount of protein increased dramatically until seven days p. c. The amount of non‐protein‐N to total‐N reached a peak at six days p. c., then declined. The chemical composition of blastocoelic fluid was influenced by the maternal condition, i. e., glucose and lactic acid were higher in superovulated (good response), overcrowded and multiparous groups than in others. While protein was lower in the overcrowded, post‐partum and superovulated groups, it was higher in others.
A new approach to mammalian cranial analysis, illustrated by examples of prosimian primates
Authors: Radinsky Leonard B.
Published: February 2005

Latex endocranial casts, which may be made without damaging the skull, reveal much of the information provided by a hemisected skull. Examination of drawings of endocasts superimposed on skulls may provide insight into the biological significance of skull and brain morphology. The high degree of cranial flexion and the globose brain shape of Daubentonia appear to be related to the functional demands of its gnawing mechanism. The broad frontal lobes of indriids are correlated with orbital orientation; differences in frontal lobe sulcal pattern suggest greater elaboration of the motor filed for the hand in indriids than in lemurids. Several features of lorisid cranial anatomy are discussed. It is suggested that, as a first approximation, increased splanchnocranial declination in small prosimians results from the necessity of accommodating relatively large eyes in a skull with a relatively small splanchnocranium.
Quantitative studies of superior cervical sympathetic ganglia in a variety of primates including man. II. Neuronal packing density
Authors: Ebbesson Sven O. E.
Published: February 2005

The volumes of a sample of primate superior cervical sympathetic ganglia were measured and related to body weight and to the number of ganglionic neurons. Estimates of volumes of the ganglia varied between 1.956 mm3 in squirrel monkey and 173.530 mm3 in a human specimen. Average cell densities for the ganglia ranged from 4,455 cells/mm3 in a human ganglion to 32,528 cells/mm3 in a squirrel monkey ganglion. Mean cell territories varied from 0.0000307 mm3 in a squirrel monkey ganglion to 0.0002245 mm3 in a human ganglion.

Analysis of the data reveals striking trends of correlation between body size, volume of ganglia, and average cell territories. Since similar correlations have been described for other types of neuronal cell aggregates, it is suggested that for any given nucleus, ganglion or cortical area, the neuronal packing density varies as a function of body size.
Further morphological and histochemical studies on the yolk nucleus and associated cell components in the developing oocyte of the indian wall lizard
Authors: Guraya Sardul S.
Published: February 2005

In March through April when the oocyte growth in the ovaries of the wall lizard (Hemidactylus) is very rapid, the yolk nucleus continues to persist through various stages of previtellogenesis. This persisting yolk nucleus and associated cell components have been studied with histochemical techniques. The spherical and dense yolk nucleus stains for protein, lipoprotein and RNA. It does not form any close morphological association with the other cell components such as the mitochondria, lipid bodies (L2), spaces or canals, diffuse sudanophilic substance and dense bodies, which are arranged into three zones round the yolk nucleus proper. The mitochondria stain for lipoprotein; the L2 bodies consist of phospholipid; the spaces do not contain any material demonstrable with histochemical techniques; and the ooplasm containing the diffuse sudanophilic substance and dense bodies shows lipoprotein, protein and RNA. Eventually, the yolk nucleus disintegrates, and its substance as well as the other cell components are distributed in the cortical ooplasm of oocytes which are ready to form the yolk bodies.

Concepts of the origin, morphology, cytochemistry and function of the yolk nucleus in the oocytes of invertebrates and vertebrates, which have come about recently through the application of cytochemical and submicroscopical techniques, are discussed.
Intraneural vascular response to defective development of the chick mesencephalon
Authors: Burda Doris J.
Published: February 2005

The development of intraneural vessels was studied in response to an induced hypermorphosis of neural tissue inthe midbrains of 38 chick embryos ranging in age from three days through 14 days of incubation. The pattern of vascularization was compared with that of normal chick embryos at comparable stages of development. In the experimental embryos, the increase in mitotic figures along the ventricular borders of the mesencephalon is accompanied by the establishment of an endoneural plexus approximately one day earlier than is the case during normal vascularization of the midbrain. This plexus also penetrates more deeply and extensively into the ependymal layer. Surface vessels and intraneural vascular elements are dilated, and the cerebrospinal fluid contains varying amounts of blood released from large intraneural vessels which protrude into the ventricle. The most prominent cerebrovascular effects seem to occur between the fourth and eighth days of incubation. Thereafter, the cerebrovascular pattern becomes more normal except for relatively few isolated hemorrhagic areas.
Structure of the eye of Haideotriton wallacei, a North American troglobitic salamander
Authors: Brandon Ronald A.
Published: February 2005

The eye of Haideotriton wallacei is more reduced histologically than those of othe troglobitic salamanders. The tiny eye is imbedded in a mass of adipose tissue. No extrinsic eye muscles are present. A rudimentary lens is present in about half of the eyes examined. In two instances the lens is surrounded by a small chamber; most eyes lack a chamber. The retina and iris are relatively undifferentiated. The relatively massive retina lacks rods and cones, an outer plexiform layer and subdivided nuclear layers. A tiny optic nerve runs to the brain.
Fine structure of the aesthetasc hairs of Coenobita compressus edwards
Authors: Ghiradella Helen , Case James , Cronshaw James
Published: February 2005

The aesthetascs, short thin‐walled pegs on the antennule flagella of Coenobita clypeatus, a terrestrial hermit crab, are similar to those of other decapod crustacea in containing the dendrites of many bipolar neurons whose cell bodies are grouped in spindle‐shaped masses beneath the bases of each hair. The dendrites contain rootlets, basal bodies, and cilia, which divide dichotomously before entering the aesthetasc, so that within the hair, each cilium becomes represented by a group of slender branches.

The aesthetascs themselves are short, blunt, and partially recumbent so that each has an exposed and an unexposed side. The cuticle on the exposed side is thinner and more tenuous than that on the protected side, and the dendrite branches are concentrated just underneath. The protected side, on the other hand, is lined with nondendritic supporting cells, and the cuticle is thicker, more lamellar, and probably less permeable.

All dendritic elements proximal to the dendrite branches are enclosed within the main body of the antennular flagellum, and the initial segments of the cilia lie within a vacuole. In these respects, the aesthetascs of Coenobita resemble the thin‐walled pegs on insect antennae more than they do those of the marine decapods thus far examined. This convergence in the terrestrial forms may be in response to the need to conserve water.
Interrelationships between developing oocytes and ovarian tissues in the chiton Sypharochiton septentriones (ashby) (Mollusca, Polyplacophora)
Authors: Selwood Lynne
Published: February 2005

Oogenesis and the relationships between oocytes and other ovarian tissues have been studied in Sypharochiton septentriones. The ovarian tissues were examined by electron microscopy and by histochemical methods.

The sac‐like ovary is dorsal, below the aorta, and opens to the exterior by two posterior oviducts. Ventrally, the ovarian epithelium is folded inwards to form a series of plates of tissue, which support the developing ova. Each ovum is attached to a tissue plate by a stalk, the plasma membrane of which is bathed by the blood in the tissue plate sinus. Dorsally, ciliated vessels from the aorta enter the ovary and open into blood sinuses in the top of the plates.

After each germinal epithelial cell rounds up to become a primary oogonium, it undergoes four mitotic divisions to give rise to a cluster of 16 secondary oogonia. Of these, the outer ones become follicle cells and the inner ones become oocytes. As in other molluses, the increases in nuclear and nucleolar volume are relatively greatest towards the end of previtellogenesis, when chromosomal and nucleolar activity are most intense. This phase of activity is accompanied by a great increase in cytoplasmic basophilia. Subsequently this basophilia is decreased during vitellogenesis, when chromosomal and nucleolar activity diminish. Fluid filled interstices appear in the cytoplasm during early vitellogenesis. Protein yolk deposition is associated with these interstices, but the lipid yolk appears to arise de novo. The follicle cells do not appear to be directly involved in oocyte nutrition.

At times during oogenesis, certain manifestations of polarity can be found in the oocyte. This polarity is based on an apical‐basal axis and can be related to the nutritive source of the oocyte, namely the blood which bathes the plasma membrane of the oocyte in the stalk.

Numerous granulated cells are present in the ovarian tissue plates and ventral epithelium as storage cells containing lysosomes, and they are capable of phagocytosis and micropinocytosis of extracellular material. A scheme is outlined whereby reserves in these cells may be incorporated into the oocyte cytoplasm. Lysosomal activity is responsible for autolysis of the cells as well as resorption of unspawned ova.
Musculature, nervous system and glands of pregenital abdominal segments of the female of Nomia melanderi Ckll. (Hymenoptera, Apoidea)
Authors: Youssef Nabil N.
Published: February 2005

The gross anatomy of muscles, the topography of nerve tissues, and the histology of the pregenital abdominal glands of Nomia melanderi Ckll. are reported in detail. The movable and fixed points of muscle attachment were utilized in establishing a system of nomenclature for a typical abdominal segment. Names of nervules correspond to those of the tissues they innervate. The points of attachment of muscles of the fifth abdominal segment are essentially the same in both Nomia and Apis, except for the second tergo‐sternal muscle which, in Nomia, has shifted its point of movable attachment to the membranous integument in front of the intersegmental membrane gland where it helps in relasing glandular secretion. The general plan of the nerves in the fifth abdominal segment in Nomia is more diffuse than in Apis, but there is no difficulty in establishing homology between the nervules of the two species. A pair of intersegmental stretch organs was found in abdominal segments 3–6. Glands of the sixth intersegmental membrane possess a reservoir with peripheral pouches both of which are absent in those of the fifth. Both types of glands have neither closing nor opening mechanisms, and neither is innervated. Release of glandular secretion is accomplished by the action of the tergo‐sternal muscles.
The fine structure of the colleterial glands of Hyalophora cecropia (Lepidoptera)
Authors: Berry Spencer J.
Published: February 2005

The structure of cells in the colleterial glands of the Cecropia silkmoth was examined. Morphologically and functionally the gland is divided into two regions, a tubular one in which columnar protein‐synthesizing cells are located, and an expanded region in which flattened cells with very different structure are most prominent. The fine structure of the latter cells which are presumed to secrete a phenolic glucoside, closely resembles that of cells described in the colleterial glands of orthopterans. The protein‐secreting cells have many features normally associated with pancreatic acinar, and other cells of similar function. Among these are extensive rough endoplasmic reticulum, an elaborate Golgi complex, and a modest number of mitochondria. Other features which are less usual in cells of this type are an elaborate secretory apparatus consisting of a cuticular tubule inserted into a microvilli‐lined cavity at the apical end of the cell, and large numbers of cytolysomes, myelin figures, and lipid droplets. A chitogenous cell with a very distinct and specific type of ultrastructure is found associated with the secretory cell. This cell type is attached to the cuticular elements of the gland, and the main features of its cytoplasm are extensive bundles of microtubules which presumably serve as supportive elements for the secretory cells.
Some histochemical and biochemical observations on the lymphatic tissues of highly inbred white Leghorns
Authors: Fennell Richard A.
Published: February 2005

Lymphatic tissues of inbred lines of White Leghorn chickens and 20‐day embryos (inbreeding coefficient exceeds 95%) were used in the experiments, e.g. line 6 was susceptible, line 7 was resistant, and line 15 I was intermediate in response to the virus. Enzyme reactions were studied in cryostat‐cut sections of tissues and in tissue minces by colorimetric procedures. Numbers of isozymes and proteins of lymphatic tissues were resolved by disc gel electrophoresis.

Colorimetric tests showed that intensities of lactate, malate, isocitrate and succinic dehydrogenase catalyzed reactions were higher in the bursae of 15 I 20‐day embryos than they were in bursae of either line 6 or 7 embryos. Intensity of dehydrogenase reactions of the spleen (15 I embryos) exceeded that found in line 6 and 7 embryos. Intensity of diaphorase reactions in the spleen and thymus was fairly uniform in all lines of embryos. Intensity of DPN diaphorase reactions in the bursae of line 15 I embryos exceeds that found in either line 6 or 7 embryos. Intensity of enzyme reactions leveled off to become fairly uniform in lymphatic tissues of chickens 3–4 weeks post hatching with the exception that dehydrogenase reactions were less intense in the thymus of 15 I chickens.

Photodensitometer scans of acrylamide gel columns showed that proteins of line 6 lymphatic tissues combined with less Amido black 10B than lymphatic proteins of either line 15 I or 7 embryos. There was fairly good agreement between concentrations of strong mobility (components 1–9) and weak mobility (components 10–16) in lymphatic tissues of all lines of embryos with the exception that strong mobility proteins were about twice as concentrated in line 15 I bursae. Variable numbers of lactate isozymes were found in the lymphatic tissues of 20‐day embryos.
The postnatal development of the pelage and ventral gland of the male gerbil
Authors: Feldman Audrey , Mitchell Ormond G.
Published: February 2005

The postnatal development of the pelage and ventral gland of male Mongolian gerbils ranging from newborn to 86 days of age was studied. The development of the gerbil pelage follows a pattern similar to that observed for other rodents. The length of the dorsal and ventral skin juvenile hair cycle was found to be 26 to 28 days with a 15 to 18 day anagen and a ten to 11 day catagen and telogen. Hair follicles in the ventral gland began growth ten days later than those of the general pelage and secondary follicles budded from the sides of primary follicles. The ventral gland area differed from the general pelage in that it lacked a panniculus carnosus. The ventral gland is a complex of pilosebaceous glands which, in the adult, fill the entire hypodermis. The length and width of the pilosebaceous canals of the gland units are greater than those of the dorsum. The period of telogen of the hair follicles in the ventral gland is very short. The mid‐ventral gland of the male gerbil appears to be a secondary sexual characteristic.
The reproductive morphology of Cnemidophorus neomexicanus X Cnemidophorus inornatus hybrid males
Authors: Christiansen James L. , Ladman Aaron J.
Published: February 2005

The morphology of the gonads and epididymides, and an analysis of selected scale characters of six hybrid males presumed to be the result of the natural mating of the all‐female whiptail lizard species Cnemidophorus neomexicanus and the bisxual species C. inornatus are presented. The histological appearance of the gonads and epididymides reveals a seasonal cyclicity with respect to the production and storage of spermatogenic elements. On the basis of the limited sample, it is postulated that some abnormality may be present in gametogenesis of these hybrid males which could be related to their chromosomal number. The data on scale characters support the interpretation that these hybrids are intermediate with respect to the parental species.
Oxidative enzyme histochemistry of the chick esophagus and proventriculus
Authors: Hinsch Gertrude W.
Published: February 2005

Succinic dehydrogenase, NAD and NADP diaphorases, choline oxidase, d‐amino acid oxidase, α‐glycerophosphate dehydrogenase, glutamic dehydrogenase, lactic dehydrogenase and aldolase were identified histochemically in the esophagus and proventriculus of the developing chick embryo. In general, the deep glands of the proventriculus reacted more strongly than the epithelium and mucous glands of the esophagus to the tests. The intensity of the enzymatic activity seems correlated with the number of mitochondria and metabolic activity of the cells.
Lymphatic capillaries in tail fin of amphibian larva: An electron microscopic study
Authors: Leak Lee Virn
Published: February 2005

The ultrastructure of lymphatic capillaries in the tail fin of Rana catesbiana larvae was investigated. With the use of a colloidal marker particle (Biological Carbon) the extent that these delicate vessels ramify throughout the fin region was demonstrated. This opaque substance also serves as a marker particle for identification of lymphatics with some degree of certainty at both light and electron microscopic levels. The cytoplasm of the lymphatic endothelial cell is abruptly attenuated beyond the perinuclear region, reaching widths as thin as 300 Å. Lymphatic Anchoring filaments are present, but to a lesser degree than noted for other species studied. Other features of interest include an extensive Golgi complex and electron dense bodies that are surrounded by a smooth surfaced unit membrane. These bodies are somewhat heterogeneous in size (500 Å up to 0.5 μ in diameter) and density. Numerous exit channels are provided by the extensive supply of lymphatics throughout the tail fin region of amphibian larva thus allowing them to serve an important function during metamorphosis. It is suggested that these vessels also act as passageways through which lysed cellular and connective tissue components may be rapidly removed during the process of tail fin resorption.
In vitro myogenesis of promuscle cells from the regenerating tail of the lizard, Anolis carolinensis,
Authors: Cox Prentiss G.
Published: February 2005

Presumptive myoblasts from the regenerating tail of the lizard plated at clonal density undergo extensive growth giving rise to large colonies. After several days in culture at 31°C some of the cells begin to round up and assume a spherical morphology. The number of rounded up cells increases over the next few days until 50 to 75% of the cells are rounded up. If the cultures are switched to a permissive medium, fusion and differentiation occur. If they are left in a nonpermissive medium fusion does not occur. Instead, the cells stretch out on the substrate and become long and attenuated or broad and strap‐like. However, differentiation may continue in some of the cells giving mononucleate cells with cross striations. Autoradiographic studies indicate that the rounded up cells represent a post‐synthesis, prefusion population of cells.
An electron microscope study of nebenkern formation and differentiation in spermatids of Murgantia histrionica (Hemiptera, Pentatomidae)
Authors: Pratt Susan A.
Published: February 2005

Mitochondria in early spermatids of many insects aggregate and form a round body, the nebenkern. The nebenkern undergoes a structural differentiation and then divides into two separate equal‐sized bodies. In the present study, nebenkerns of Murgantia histrionica, a Hemipteran insect, were reconstructed using electron micrographs of serial sections to determine how the mitochondria transform into the two separate bodies.

Newly formed nebenkerns are made of one piece, an anastomosis of rod‐like segments. Some segments interconnect to join networks of rings. Each network interlocks with another similar network, but networks which interlock are connected with each other by other segments of the nebenkern. Later, the entire nebenkern is made of two unconnected and interlocked networks of rings. The nebenkern appears to remain bipartite during subsequent differentiation. Since the two pieces are interlocked, breaks must occur before the pieces can separate. As breaks occur, each network transforms into a set of curved sheets, producing a nebenkern made of four concentric layers. The three outer layers are each made of two curved sheets which surround a bipartite central core. The surface sheets meet at a furrow in the surface of the nebenkern; segments in each layer are roughly symmetrical with each other about the plane in which the furrow lies. Rod‐like segments join alternate segments. The number of layers then decreases to three, and later, to two. These nebenkerns resemble four‐layered nebenkerns, but fewer connections between alternate segments are present. The two pieces constituting the nebenkern probably separate after most of the latter connections disappear. Hypotheses to account for the observed changes in nebenkern structure are presented.
Studies on hydroid differentiation. III. The replacement of hypostomal gland cells of Podocoryne carnea
Authors: Braverman Max
Published: February 2005

Pulse labeling with tritiated thymidine has permitted the identification of a progenitor cell compartment at the base of the hypostomal glandular ridges of the marine hydroid Podocoryne carnea. This progenitor compartment produces cells which move out on the ridges differentiate as digestive gland cells, and are ejected into the gastro‐vascular cavity. Spherous gland cells of the body appear not to be part of this circumscribed replacement system. There appears to be no proximal movement of gastrodermal cells in the body of this marine hydroid.
The adult cervicothoracic musculature of the cockroach, Nauphoeta cinerea (Olivier)
Authors: Storch R. H.
Published: February 2005

The cervicothoracic musculature of the adult cockroach, Nauphoeta cinerea (Olivier) is described for the first time. The adult thoracic ventral intersegmental muscles are compared with those of the nymph and of the adult cockroach, Periplaneta americana (Linnaeus).
Thoracic structure of the adult mecopteron, Bittacus strigosus Hagen (Mecoptera: Bittacidae)
Authors: Storch R. H. , Chadwick L. E.
Published: February 2005

The thoracic skeleton and musculature of the adult bittacid mecopteron Bittacus strigosus Hagen is described. In its musculature, Bittacus shows only moderate differences from two panorpids (Neopanorpa, Panorpa) that have been studied by Maki ('38) and by Hasken ('39), respectively. Not only are these three genera much alike in their musculature generally, but in all of them, and in Boreus (Boreidae) too, the mesothorax is extremely similar to the metathorax. Functional emphasis (for flight) on either of the two pterothoracic segments has not appeared among neuropteroid insects at the metopteran evolutionary level.

Although the “snowfleas” of the genus Boreus possess striking alterations of pterothoracic structure in comparison with other mecopterons (Füller, '54, '55), these are related to their unusual activities and have not, to any great extent, affected the two pterothoracic segments differentially.

In terms of thoracic specialization, the overall mecopteran pattern represents a stage somewhat advanced beyond the primitive conditions exemplified by the Megaloptera and certain coleopterous larvae, but one that is in general less highly developed than is charatceristic of such neuropteroid orders as the Siphonaptera, Diptera, Trichoptera, and Lepidoptera.
Fine structural features of developing leg discs of the blowfly, Sarcophaga bullata (Parker)
Authors: Chiarodo Andrew J. , Denys Francis R.
Published: February 2005

The mesothoracic leg discs of the blowfly, Sarcophaga bullata (Parker) were studied by electron microscopy during the third larval instar. As the peripodial membrane and separation form, the cells of the disc become elongated and perpendicularly oriented toward the separation. The cellular organelles do not undergo significant changes until the late third instar. At this time, there is a significant increase in the amount of granular endoplasmic reticulum and in the number of inclusions, particularly in those cells located more deeply in the disc. Nucleolar enlargement and an increase in the number of mitochondria are also observed at this time.

The cells at the border of the disc form a columnar epithelium whose surface develops microvilli‐like projections. These projections. These projections reach their maximum development towards the end of third instar.

It is suggested that some of the observed changes may represent a phenotypic expression of secretion of cuticular material.
The influence of gonadectomy on sexual characters in the Japanese quail
Authors: Kannankeril J. V. , Domm L. V.
Published: February 2005

Sinistral ovariectomy in the Japanese quail resulted in some hypertrophy of the rudimentary right gonad in about 80% of the cases. The hypertrophied right gonads were composed of cords of epithelial origin, fat laden cells and a connective tissue stroma containing masses of lymphocytes. Neither cortical tissue nor germ cells were found in any of the gonads. In some cases regeneration of a testis‐like tissue was seen on the site of removed left ovary. This, however, did not alter the effects of ovariectomy on rudimentary right gonad, accessory sex organs, plumage or sexual behavior. Neither Wolffian nor Müllerian ducts exhibited hormonal stimulation in poulards showing hypertrophy of right gonad with exception of the latter in two poulards. Early orchiectomy inhibited growth and differentiation of the cloacal gland. This organ revealed no noticeable stimulation in poulards showing hypertrophied right gonads. Castration produced no significant changes in plumage of males. Similarly, sinistral ovariectomy did not effect the first juvenile, but the second juvenile, adult winter and summar plumages changed to the male type. However, the plumage of some of these poulards began to revert to the female character as early as 10 to 12 weeks following ovariectomy. The behavior of capons and poulards revealed no conspicuous difference and neither showed any masculine behavior. The average weight of adult females was 20 to 30 gm above that of adult males whereas that of capons was above normal males and that of poulards below normal females. The average weight of capons was somewhat above that of poulards.
The distribution of peritubular matrix in human coronal dentin
Authors: Weber Dennis F.
Published: February 2005

Thin semi‐serial ground sections of coronal dentin were examined radiographically. The bulk of the coronal dentin was characterized by the majority of the tubules having a distinct peritubular zone. With the exception of the tubules running from the tip of the cusp to the pulp cornu, the bulk of peritubular matrix forming the walls of the tubules was disposed eccentrically. The matrix was thicker on the cervical sides of the tubule than it was on the incisal sides. In a relatively narrow layer of the coronal dentin between the bulk of the dentin and the predentindentin border area the thickness of the peritubular matrix varied considerably. It was extremely narrow or absent in some tubules and reached its greatest thickness in others. The tubules in the predentin border area showed little or no evidence of peritubular matrix. The area of dentin beneath the central developmental groove differed somewhat from the bulk of the dentin. Many of the tubules at all levels of this area showed little radiographic evidence of peritubular matrix. Obliterated tubules were seen in some of the sections taken immediately above the predentin‐dentin border area in the region of the pulp cornu and were always seen at the junction of the mantle dentin and the circumpulpal dentin beneath the central developmental groove.
Coordinated development in the fly foot: Sequential cuticle secretion
Authors: Whitten Joan M.
Published: February 2005

Development of the adult fly foot falls into clearly defined phases of cell division, growth, cuticle secretion and cell death. The pulvillus is composed dorsally of two giant cells and ventrally of thousands of minute tenent cells; the former produce the dorsal footpad cuticle and the latter the thousands of tenent hairs. Cell divisions are still occurring in future tenent cells when increase in size of the cells and in polyteny of the chromosomes is already occurring in the two dorsal cells. Also cell death occurs considerably earlier in the tenent cells, yet the sequential secretion of some six cuticular layers takes place at comparable times in dorsal and ventral cuticles. The cuticular layers formed are, in their order of secretion: ecdysial membrane, cuticulin of the epicuticle, dense exocuticle, homogeneous exocuticle, an intermediate layer, wax of the epicuticle, and an extensive mass of endocuticle. The ecdysial membrane seems to perform an important mechanical role in maintaining the shape of the delicate cytoplasmic projections of the tenent cells, before and during cuticle secretion, and in establishing the cuticular pattern of ridges in the dorsal cuticle. Comparisons are made with trichogen cell cuticle development and with tracheal cuticle. Tracheal, trichogen and dorsal footpad cuticle patterns are compared.

Details of giant cell activity provide a working basis for studies of nuclear‐cytoplasmic interactions, and the whole system raises many unsolved problems in the general field of cell differentiation and pattern formation.
A fine structural analysis of the statocyst in Aplysia californica
Authors: Coggeshall Richard E.
Published: February 2005

Each statocyst in Apylsia californica contains 13 neurons. The statocyst nerve, which connects each statocyst to the cerebral ganglion, contains only the 13 axons of the statocyst neurons. The size of the statocyst, the number of neurons in the statocyst, and the average axonal diameter does not change even though the statocyst nerve lengthens greatly as the animal enlarges. A description of the statoconia and the supporting cells in this organ has been given. This prepazation may be useful for microelectrode studies designed to test whether the gap and cytoplasmic specializations that are used to identify active synapses, are necessary for all types of chemical synaptic transmission.
A mechanism for rapid transport of colloidal particles by flounder renal epithelium
Authors: Bulger Ruth Ellen , Trump Benjamin F.
Published: February 2005

Large quantities of colloidal particles were rapidly transported around the junctional complex into the lateral intercellular spaces by flounder renal epithelial cells. Large invaginations containing particles developed in the apical cytoplasm of cells when tracer particles were injected into the tubular lumens. Some membranebounded profiles containing particles appeared close to the lateral intercellular spaces. Particles were then found in the lateral intercellular spaces, between the basal plasmalemma and the basement membrane, and within the basement membrane. It is suggested that this transport might operate in situ and provide a morphological mechanism to explain a type of protein transport noted in the renal tubules of another flounder species by Maack and Kinter ('67). It is interesting to consider that perhaps a similar mechanism for the transport of intact proteins might also operate in mammalian nephrons as well.
Regeneration and supernumerary limb formation under sparsely innervated conditions
Authors: Thornton Charles S. , Tassava Roy A.
Published: February 2005

Normally, urodele limb regeneration is nerve‐dependent. Reduction in nerve‐dependency has been reported for regenerating, transplanted newt limbs (Singer and Mutterperl, '63). Aneurogenic limbs can regenerate without nerves (Yntema, '59). Induction of supernumerary limbs may be obtained from aneurogenic limbs of larval Ambystoma after transplantation orthotopically to innervated larvae and with normal nerve ingrowth to the limb transplant prevented by repeated section of brachial nerves. Of the 13 (of 43) grafts with supernumeraries, nerve counts showed 11 with 0–5; 1 with 5–10; and 1 with 20+ fibers. Orthotopically grafted aneurogenic limbs allowed to become innervated showed 14 supernumeraries in 49 grafts. This supernumerary limb induction is thus not nerve‐dependent.

Normally, innervated larval Ambystoma limbs grafted orthotopically and heteroplastically regenerated in 17 of 37 cases after repeated section of brachial nerves. Of the 17 regenerates nerve counts showed 4 with 0–5; 5 with 5–10; 7 with 10–19; and 1 with 20+ fibers. Larval limbs heteroplastically transplanted may require very few or no nerves for regeneration.
A rapid method for detecting malformations in rat fetuses
Authors: Barrow Mark V. , Taylor W. Jape
Published: February 2005

A rapid method for examining rat fetuses is presented. The technique consists of fixing the fetuses in Bouin's solution, serially sectioning the head, neck and lower trunk with a razor blade and doing sagittal sections of the heart after opening the thoracic cavity. Examples of sections from normal 20 day rat fetuses are given as well as some with the following abnormalities: cleft palate produced by chlorcyclizine and eye and heart malformations resulting from anti‐adult rat kidney serum.
The occurrence of intercellular bridges during oogenesis in the mouse
Authors: Ruby John R. , Dyer Robert F. , Skalko Richard G.
Published: February 2005

A fine structural analysis of fetal mouse ovaries reveals the presence of intercellular bridges between developing oocytes. These bridges, which connect two or more oocytes, are most frequently seen prior to the dictyate stage of meiotic prophase. The intercellular connections are limited by a tri‐laminar membrane which is continuous with the oocyte plasmalemma. A characteristic feature of all bridges is the presence of an electron‐dense material on the cytoplasmic side of the limiting membrane. Since this dense material is a constant and conspicuous component of the entire bridge, identification of these connections is possible in all planes of section. In cross section, the bridges are usually cylindrical, while in longitudinal section, a variety of configurations are observed. Oocytes connected by intercellular bridges exhibit a highly developed Golgi complex which is frequently localized in the region of the cytoplasmic continuities. Vesicular elements, apparently derived from the Golgi, are routinely observed within the boundaries of the bridges. Other cytoplasmic organelles, including rough and smooth endoplasmic reticulum, free ribosomes and mitochondria, are also seen in these bridges. The presence of these vesicles and organelles within intercellular bridges suggests that these connections may provide a means for transfer of organelles and other substances from one oocyte to another. It may be, therefore, that intercellular bridges are important for the nourishment and maturation of certain selected oocytes as well as for the synchronization of meiotic events.
Silk secretion in sawflies
Authors: Kenchington W.
Published: February 2005

The serigenous glands of a number of different sawfly larvae have been examined. Silk is secreted by pear‐shaped cells which may be fused together in pairs or triplets, or exist simply as free, single cells. The cells are arranged in numerous groups attached to a pair of wide silk reservoirs by means of short canals. Each gland cell contains a large, irregular, ramifying nucleus and an intracellular duct which receives droplets of synthesised silk protein. Two modifications of this basic arrangement are described. It is suggested that the secretory cells are dermal gland cells, and that the intracellular duct is a rudimentary end‐apparatus. A comparison is made between these and some other types of dermal gland cell found in insects.
Tentacular and oral‐disc regeneration in the sea anemone, Aiptasia diaphana. I. Sequential morphological events in distal‐end restitution
Authors: Singer Irwin I. , Palmer John D.
Published: February 2005

The complete regeneration of a new oral‐disc and tentacles has been observed and described for Aiptasia diaphana. These structures are regenerated quite rapidly: seven to ten days at 20°C. At three days post‐amputation, the new primary, secondary, and tertiary tentacle buds begin to develop in direct association with the underlying primary, secondary, and tertiary septae (respectively) of the column, suggesting that the latter organize the form of the regenerating oral‐disc. Two days after amputation, the zooxanthellae of the presumptive oral disc arrange themselves into a ring which quite precisely delimits the area from which the tentacle buds will form. In spite of its suggestive proximity, this accumulation of algae plays no role in the induction of tentacle buds as was shown by studying regeneration in anemones which essentially lacked large quantities of these symbiotic algae.

Cuts perpendicular to the longitudinal axis of the column result in an equal rate of tentacular regeneration around the entire circumference of the presumptive oral disc. Oblique amputations foster an asynchronous regeneration: the tentacle buds of the distal‐most area of the severed column are larger and regenerate much sooner than those of the proximal region. Similar results were obtained by studying anemones which were cut perpendicular to their longitudinal axes at different levels along the column. The data suggest that an oral‐aboral gradient exists concerning the time required for the initiation of tentacle budding and the rate of tentacle regeneration.
Specialized basophilic cells in the ventral lobe of the pituitary of the smooth dogfish, Mustelus canis
Authors: Tewinkel Lois E.
Published: February 2005

The ventral lobe of the adenohypophysis of the smooth dogfish, Mustelus canis, a viviparous elasmobranch, has been found to possess distinctive cells identified as basophils on the basis of staining properties. At maximum size, such a cell consists of a distended vesicle containing PAS‐positive, AF‐negative material surrounded by a thin envelope of cytoplasm and an eccentric nucleus. In earlier stages of these cells, vesicles are small or absent and granules in the more abundant cytoplasms are AF or Alcian‐positive.

Basophil numbers are high in pre‐ovulation and mid‐ovulation females, decrease markedly after the end of ovulation until embryos are about 1 cm long then increase greatly during August and September while embryos grow to 8 cm in length. Early high counts, if these basophils are gonadotropes, may be correlated with stimulation of the ovary and ovulation; reduced numbers suggest inhibition, possibly by ovarian hormones for a period, while subsequent increase may indicate indirect involvement in uterine conditions in this viviparous species. Conclusion are, admittedly, tentative as specimens were available during only a fraction of the ten month gestation period.
The structure of the rectal pads of Periplaneta americana L. With regard to fluid transport
Authors: Oschman James L. , Wall Betty J.
Published: February 2005

The rectum of Periplaneta americana L. is lined with cuticle and has six radially arranged cushion‐shaped thickenings, the rectal pads, composed of columnar cells. Narrow strips of simple rectal cells lie between the pads. Tall junctional cells form a thin but continuous collar around the pads where they join the rectal cells. The epithelium is surrounded by a layer composed of circular and longitudinal muscles and connective tissue. This layer of muscle and connective tissue is innervated and tracheated, and is separated from the pad surface by a subepithelial sinus. Fluid flowing through the sinus enters the haemolymph through openings in the muscle layer whre large tracheae penetrate. These openings can be sealed by muscle contractions that appress the muscle around the openings against the pad surface. The tracheae pass on into the pads, following basement membrne‐lined indentations of the pad surface. Within the pad tracheolar cells send fine branches between the cells. Near the apical and basal surfaces the lateral membranes of pad cells are bridged by septate desmosomes that form a continuous band around the cells. Between apical and basal septate desmosomes is an interconnected labyrinthine system of intercellular spaces. There are three kinds of space, dilations and apical sinuses, both of variable size, and narrow communicating channels about 200 Å wide. The membranes of the latter have mitochondria closely associated with them. Continuity between the system of spaces and the subepithelial sinus is established by the basement membrane‐lined invaginations of the basal surface where tracheae penetrate between pad cells. Apical surfaces of the pad cells are highly infolded and are also associated with mitochondria. However, unlike the lateral membranes facing the narrow channels, the apical membranes have a cytoplasmic coating of particles. Both associations of mitochondria with membranes constitute discrete structural entities that are found in many transporting epithelia, and we have termed them “plasmalemma‐mitochondrial complexes.” As the rectal pads are organized into systems of spaces that ultimately open in the direction of fluid movement, existing models of solute‐coupled water transport can be applied. However, the rectal pads are structurally more complex than fluid‐transporting tissues of vertebrates. This complexity may be related to the ability of the rectum to withdraw water from ion‐free solutions in the lumen. We present a structural model involving solute recycling to explain the physiological characteristics of rectal reabsorption.
Morphologic variation in the cranium and mandible of the white‐tailed deer (Odocoileus virginianus): A comparative study of geographical and four biological distances
Authors: Rees John W.
Published: February 2005

Several biological distances based on cranial and mandibular variation among breeding groups of white‐tailed deer were calculated and compared with geographic distances among the groups. Distances based on epigenetic variation among ten groups were calculated using 16 non‐metric variants of the cranium and mandible. Penrose's size and shape distances and Mahalanobis' D2 distance were calculated for 11 groups; the calculations were based on seven skeletal and seven dental metric variables of the mandible.

The biological distances were correlated with geographic distance as follows: the epigenetic distance, 0.74; Penrose's shape distance, 0.71; Penrose's size distance, 0.45; and Mahalanobis' distance, 0.37. All correlations were significant at the 0.01 level. The epigenetic and Penrose shape correlations were significantly higher than the Mahalanobis correlation.

Because of the conditions under which the breeding groups were selected, it was assumed that genetic affinites among the groups would be a function of geographic distance. The results suggest that the epigenetic distance and Penrose's shape distance reflect genetic affinities among groups better than do the Penrose size and Mahalanobis distances.
Ultrastructure of the mouse tracheal epithelium
Authors: Hansell Margaret M. , Moretti Richard L.
Published: February 2005

The ultrastructure of mouse tracheal epithelium was examined. The three cell types, basal cells, ciliated cells and goblet cells, described for other mammalian trachea were found to be present although goblet cells occurred only rarely. A cell type, termed the nonciliated cell, not described in other mammalian trachea was frequently found in mouse tracheal epithelium. These cells contained abundant smooth and rough endoplasmic reticulum, free ribosomes, a large Golgi complex, and many mitochondria. There were many vesciles containing an electron dense material near the luminal surface of these cells; these cells were positive for PAS. These features suggested a secretory function for the cells. This, along with the scarcity of goblet cells, suggested that the nonciliated cells of mouse tracheal epithelium fulfill the function of the goblet cells found in other mammalian trachea.
Fine structural observations on nuclear maturation during spermiogenesis in Hydra littoralis
Authors: Weissman Anne , Lentz Thomas L. , Barrnett Russell J.
Published: February 2005

Cytodifferentiation during spermiogenesis in Hydra littoralis was studied at the fine structural level. Concentration of nuclear material as well as specific orientation of granular and filamentous nuclear elements are apparent in two regions of the early spermatid: where the nuclear envelope is in contact with mitochondrial membranes at one pole of the cell and at an opposite region where the nucleus is closely apposed to the plasma membrane. Ultimately the mass of condensed nuclear material becomes concentrated at the mitochondrial pole of the cell. Additional electron‐dense material is extruded from the nucleus into a large vacuole which is in continuity with the nuclear membrane as well as associated with Golgi lamellae and vesicles. Eventually all residual cytoplasm is sloughed, leaving the nucleus, mitochondria, and flagellum. These observations are suggestive of nucleocytoplasmic interactions during development, especially influences of mitochondria and plasma membranes on chromatin condensation.