bluuebunny/crossref_metadata_2025_split huggingface dataset:
The food pump of Aphelocheirus aestivalis F. as compared with that of typical Naucoridae (Heteroptera)
Authors: Parsons Margaret C. 
Published: February 2005

AbstractThe heteropteran cibarium forms a sucking pump which conveys fluid foods into the pharynx. The food pumps of Hydrocorisae have the additional function of grinding or filtering particulate matter; they contain ridges, hairs, and sclerotized processes which have probably evolved at least twice among the hydrocorisine families. Aphelocheirus, like the Naucoridae, possesses a modified anteclypeus and a tripartite type of food pump. The main sucking action occurs in the pump's anterior and posterior regions, while the middle region is specialized for grinding and filtering. The anteclypeus has broadened and fused with other parts of the cranium, and is thus braced against the pull of the powerful cibarial dilator muscles. In the Naucoridae the three regions of the pump have the same functions as those of Aphelocheirus. The pumps of the five naucorid genera here studied are structurally very similar to each other but differ considerably from that of Aphelocheirus. Cibarial morphology, as well as respiratory differences, thus supports the contention that Aphelocheirus is not a member of the Naucoridae but should be placed in a separate family.
Musculature, nervous system and glands of metasomal abdominal segments of the male of Nomia melanderi Ckll. (Hymenoptera, Apoidea)
Authors: Youssef Nabil N. 
Published: February 2005

AbstractEach muscle of the third metasomal segment of the male of Nomia melanderi Ckll. is described in detail. The points of attachment of each muscle are compared with their homologs in other pregenital segments and with their homologs in the female. The function desgnated for each muscle describes its action alone or in conjunction with other muscle(s). New names are given to genital muscles by referring in the name to their points of attachment. Each intratergal muscle has homologous points of attachment in the pregenital segments of both sexes. The median tergo‐dorsoplical muscle of the seventh segment and the oblique tergo‐dorsoplical muscle of the eighth segment have changed their points of attachment. The intrasternal muscles are modified to suit the needs of courtship and mating, thus they are different from their homologs in the female. The spiracular muscles are well developed in all segments except the eighth, where the sterno‐spiracular muscle is absent. The extrinsic genital muscles are derived from the intrasternal muscles of the eighth and ninth segments. The parameral and volsellar muscles are reduced in number. The aedeagal muscles, except the aedeago‐phallic, have retained similar points of attachment to those found in primitive Hymenoptera. The topography of the metasomal nervous system is reported in detail by following each nerve and nervule to its termination. The study shows that (at least in Nomia) the criterion of nerve‐concentration should not be used alone to indicate evolutionary levels. To accommodate the morphological changes in the terminal segments the Anterior and Posterior Lateral Nerves have migrated to new locations. The pattern of nerve topography (even at the nervule level) is homologous both in the different pregenital segments and between the sexes. The fact that homology does not exist between the external genitalia of the male and the modified ovipositor of the female supports the thesis that the male genital capsule is of phallic rather than prephallic origin. A pair of intersegmental membrane glands located between the seventh and eighth sterna is described. These glands may be the source of a pheromon responsible for gregariousness among “sleeping” males.
The ontogeny of interstitial cells in Pennaria tiarella
Authors: Summers Robert G. , Haynes Julian F. 
Published: February 2005

AbstractThe interstitial cells of Pennaria tiarella differentiate exclusively from the central endoderm of the planula. Shortly after their appearance, most of the interstitial cells become cnidoblasts. Subsequently, as the larva transforms into a polyp, both cnidoblasts and interstitial cells migrate from the endoderm, through endoblast and mesoglea, into the ectoderm. It is suggested that some interstitial cells remain in the endoderm and differentiate into the gland and mucous cells of the polyp gastroderm.
The body wall of cheilostome Bryozoa. II. Interzoidal communication organs
Authors: Banta William C. 
Published: February 2005

AbstractCommunication organs (septulae) of cheilostome Bryozoa are more complex than perviously believed. Annuli, present only in lateral septulae, are thickenings of the intercalary cuticle. Each communication pore is filled with a ring‐like “pore cincture,” through which project a pair of “special cells.” Septulae of all species examined (10 species from 6 families) can be considered modifications of the same structure, varying only in degree of calcification and number of communication pores.External walls, including basal and lateral walls, are best defined as reinforcements of the ectocyst, which is derived by intussusception from the primary cuticle of the ancestrula. The lateral ectocyst must be considered a double layer formed by invagination of the distal ectocyst. Internal walls are developed by apposition from inner parts of the ectocyst; they include pore plates and transverse walls.External walls are laid down first. Lenticular masses develop unilaterally on the uncalcified lateral ectocyst; the pore plate develops by apposition from the interior part of the ectocyst. Depending on the species, the pore plate may or may not be calcified at the time of its formation. Communication pores are formed when the developing pore plate abuts against embryonic special cells. The septular ectocyst never calcifies; it breaks down when the pore plate is complete.Some ascophorans undergo “reparative budding,” in which new zoids are formed within dead zoecia. Hollow, ectocyst‐covered buds lined with blastemic epithelia are produced from septulae of live zoids; adjacent buds may fuse.These findings are consistent with the view that lateral septulae are aborted zoids and that pore plates represent transverse walls.
Studies on the nature and localization of acid phosphatase in normal and lens‐regenerating urodele eyes. I. Histochemical localization
Authors: Miller Neil R. , Rafferty Nancy S. 
Published: February 2005

AbstractHistochemical procedures for acid phosphatase in normal and lens‐regenerating eyes of the urodele Diemictylus viridescens demonstrate activity in a variety of structures. In the normal urodele eye, acid phosphatase is present in conjunctival and corneal epithelial cells and associated glands, in blood vessel endothelium and posterior epithelial cells of the iris, in the anterior lens epithelium, and in the cytoplasm of the optic nerve. Acid phosphatase in the lens‐regenerating eye is localized in the same structures as in the normal eye as well as in increased amounts in the corneal epithelial cells and stromal macrophages at the lentectomy wound site and in the posterior portion of the developing lens during completion of differentiation of primary into mature lens fibers characterized by loss of many intracellular organelles. On the basis of these histochemical findings, it is proposed that hydrolytic lysosomal enzymes play an important role in the processes of cellular and intracellular destruction and synthesis which occur during Wolffian lens regeneration in the urodele.
The bulbus cordis and its septa in Sphenodon punctatus
Authors: Hart Nathan H. 
Published: February 2005

AbstractTwo embryos of Sphenodon punctatus, measuring 17.4 mm and 25.2 mm in length, were used in examining the arrangement of the septa and associated vessel pattern in the bulbus cordis. As in other reptiles, two septa subdivide most of the bulbus into three arterial vessels. The aortico‐pulmonary septum passes through an angle of about 160° in its descent toward the ventricle. The aortic septum describes an angle of about 150°. Both partitions terminate anterior to the level of the ventricle, leaving an undivided remnant of the bulbus cordis from which the arterial vessels spring. When compared to other reptilian embryos whose bulbi have been studied in detail (i.e., Chrysemys and Aristelliger), Sphenodon shows similarities in the proximaldistal arrangement of the arterial apertures, the mode of descent of the bulbar septa, and the endocardial cushions, which comprise the bulbar septa. The rotation of the septa, however, is substantially different from that observed in the turtle and the lizard so far studied. The aortico‐pulmonary and aortic septa in Sphenodon spiral through angles greater than those in Chrysemys and Aristelliger. This pattern in Sphenodon appears to represent a primitive phylogenetic feature in terms of the evolution of the bulbus in reptiles.
Sequence of ossification in the skeleton of growing and metamorphosing tadpoles of Rana pipiens
Authors: Kemp Norman E. , Hoyt Judith A. 
Published: February 2005

AbstractThe order of ossification of bones in the skeleton of Rana pipiens during larval growth and metamorphosis has been determined from observations on specimens fixed in 70% alcohol and stained with alizarin red S. The axial skeleton ossifies in a generally cephalo‐caudal sequence, beginning with the parasphenoid bone at Taylor‐Kollros stages IV‐IX, followed by vertebrae (V‐IX) and then the urostyle (IX‐XIV). Exoccipitals (VII‐IX), frontoparietals (XI‐XII) and prootics (XIII‐XVII) are additional cranial bones which successively ossify before metamorphosis. With the onset of metamorphosis at stage XVIII jawbones and rostral bones of the skull ossify in the following succession: premaxilla, maxilla, septomaxilla, nasal, dentary, angular, squamosal, pterygoid, prevomer, mentomeckelian, quadratojugal, palatine, columella, posteromedial process of “hyoid.” The sphenethmoid does not ossify until after metamorphosis.Ossification of limbbones begins with the femur or humerus at stages X‐XII and progresses proximo‐distally to the phalanges by stages XIII‐XV. Carpals, however, do not ossify until stage XXV or after metamorphosis. The ilium of the pelvic girdle begins to ossify at stages X‐XII, but the ischium is delayed until stages XX‐XXIII. Scapula and coracoid of the pectoral girdle undergo initial ossification at stages XII‐XIV, suprascapula and clavicle at stages XIII‐XV. The sternum does not begin to ossify until stage XXIV. The possible role of thyroid hormones in stimulating osteogenesis is discussed.
The fine structure of the tegument of Tylocephalum metacestodes: With emphasis on a new type of microvilli
Authors: Rifkin Erik , Cheng Thomas C. , Hohl Hans R. 
Published: February 2005

AbstractElectron microscope studies on Tylocephalum metacestodes embedded in the tissues of the oyster, Crassostrea virginica, have revealed that the tegument of the larval tapeworm is comprised of an external and an internal level which are partially separated by a basal lamina and two layers of muscles. The outer tegumentary level is comprised of an anucleate, cytoplasmic syncytium in which are embedded large and small vesicles and mitochondria. Surfacial hooks are also embedded therein. The internal level is comprised of relatively large discrete cells including mitochondria, rough endoplasmic reticulum, and large and small vesicles. These cells are intermittently connected with the external level by cytoplasmic bridges.Arising from the external level are unusual microvilli each of which terminates as a spherical vesicle. The stem of each microvillus is covered by a unit membrane which is continuous with that overlaying the body surface. In addition, each microvillus includes an external layer of medium electron density, a medial layer of intense electron density, and a core of heterogenous, medium electron density. These structures may be intertwined and bundles can be observed at the light microscope level as fibril‐like projections from the parasite's body surface. One of their possible functions may be to prevent intimate contact between the encapsulating fibers of host origin and the parasite's body surface. In addition, the contraction and distention of the circular muscles result in microvillar movement which may keep the surrounding host fluids, including those of nutritional importance to the parasite, in a state of flux thus hypothetically permitting more uniform uptake.The abundance of vesicles in the syncytial external level of the tegument appears to be characteristic of the more primitive marine cestodes belonging to the orders Trypanorhyncha and Lecanicephala.
The lizard ear: Cordylus, platysaurus and Gerrhosaurus
Authors: Wever Ernest Glen 
Published: February 2005

AbstractIn further consideration of the lizard ear, the fine structure of the cochlea has been investigated and related to auditory sensitivity in members of the family Cordylidae. The ear of this group of lizards is unusual in that a tectorial membrane is present only in a modified and seemingly vestigial form, and this membrane makes no connections with the auditory hair cells. These cells are provided instead with a series of sallets, small bodies extending in a single row through the dorsal and middle regions of the cochlea, where they rest upon the tips of the ciliary tufts and evidently bring about a stimulation of the hair cells because of their inertia. At the ventral end of the cochlea this line of sallets ends, and here is a single, relatively enormous structure, the culmen papillae, that serves a similar purpose for a large group of hair cells. Consideration is given to the manner of stimulation of the auditory sense cells in these species in relation to others with the usual arrangements involving connections between the ciliary tufts and a tectorial membrane.Included also is a study of a species of Gerrhosaurus, which some have included in the cordylid family and others have placed in a family of its own. The cochlear structure in this species is similar to that of the cordylids in many respects but differs in the ventral region, where instead of the culmen there is a heavy tectorial plate, similarly covering a large number of hair cells but connected to a tectorial membrane.The functioning of these ears is assessed in terms of the cochlear potentials, and is found to vary with species from better than average to excellent in comparison with other lizards investigated. The structural differentiation also is of fairly high degree, and hence it appears that ears without tectorial connections, or with such connections only in a limited region of the cochlea, can perform in a highly serviceable manner.
Reproduction, reproductive organs, and meiosis in the bisexual non‐parthenogenetic mite Caloglyphus mycophagus, with reference to oocyte degeneration in virgins (Sarcoptiformes: Acaridae)
Authors: Heinemann Richard L. , Hughes Roscoe D. 
Published: February 2005

AbstractMeiosis is described in virgin females, inseminated females and males of the acarid mite Caloglyphus mycophagus (Megnin). The observed sex determining mechanism is an XO‐type with the male having a diploid chromosome number of 15. Oogenesis in mated females is regular. Pachytene is the earliest meiotic stage which is readily identifiable. At metaphase I eight bivalents are observed. Both products of the first maturation division divide at the second maturation division. After the fusion of the pronuclei either 15 or 16 chromosomes are observed in cleaving eggs.Nurse cells are not observed during the growth period of the oocyte. Such oocytes are attached to a central structure of the ovary by a cone‐shaped organelle. At this stage the nucleus appears as a germinal vesicle; a nucleolus is present and the diffuse chromatin appears to extend from the nucleolus to the nuclear membrane. Nuclear extrusion bodies can be seen adjacent to the nuclear membrane both within and outside of the nucleus.Virgin females do not oviposit. The aberrant morphology and behavior of bivalents in post diakinetic oocytes which have not been penetrated by a sperm are described. Neither chromatin nor a chorion could be demonstrated in aberrant oocytes situated in the oviduct. It is suggested that oocyte degeneration in virgins is an adaptive feature in an animal order in which parthenogenesis is the more common mode of reproduction.
Histogenesis of the cuticle of the adult flies, Sarcophaga bullata and S. argyrostoma
Authors: Fogal W. , Fraenkel G. 
Published: February 2005

AbstractSequential patterns of cuticle deposition and “melanization” in the imaginal cuticle of Sarcophaga argyrostoma in parts of the body darkening before or after emergence are examined on a histological basis. The patterns in the cuticles examined range from a simple absence of “melanization” to a complex of histological changes involving “melanization” and deposition. Ultrastructural changes in the post‐emergent cuticle of Sarcophaga bullata during the hardening and darkening process and cuticle deposition are described.
Inter‐strain differences in the development of the pattern of periplasm distribution during cleavage of honeybee eggs
Authors: Maul Volprecht 
Published: February 2005

AbstractDuring cleavage of honeybee eggs two peaks arise in the longitudinal distribution pattern of the periplasm which coincide with the site of the differentiation center and the site of a mesodermal center. A very similar pattern is exhibited by the dorsal plasmstrip, a narrow band of thicker periplasm which is formed during cleavage along the dorsal midline of the egg. The present paper describes the development of the dorsal plasmstrips of two inbred strains of honeybees during early cleavage stages. Differences between the two strains reside in the total size of their dorsal plasmstrips and in the timing of the formation of the anterior peak which coincides with the site of the differentiation center. The bearing of these findings upon embryological studies is discussed.
The interphalangeal area of Rana pipiens: A light and electron microscopic study of the development of a fibrocartilaginous joint (symphysis)
Authors: Joyce Stephen J. , Cohen Alan S. 
Published: February 2005

AbstractThe development of the distal interphalangeal joint in Rana pipiens hind limb was studied by light and electron microscopy. The joint was found to be a symphysis since the two articular surfaces originally capped by hyaline cartilage were separated by a joint area filled with fibrous connective tissue which ultimately was replaced by fibrocartilage. Ultrastructural studies demonstrated that the joint area development was divided into three phases. Phase I was concerned with the undifferentiated mesenchymal cells, phase II with fibroblastic and chondroblastic development, and phase III with the appearance of fibrocartilage. Changes in the cytoplasmic organelles of fibroblasts and chondroblasts, surrounding extracellular matrix, and factors related to extracellular matrix formation were described and discussed.
The effect of aging on the rat submandibular gland: An ultrastructural, cytochemical and biochemical study
Authors: Bogart Bruce I. 
Published: February 2005

AbstractThe effect of aging on the rat submandibular gland was studied by using ultrastructural, ultrastructural cytochemical and biochemical techniques. There was an age‐related clumping of the nucleolar‐associated and peripheral chromatin in many of the acinar cells and a decrease in the number of cisternae of rough endoplasmic reticulum. Many aged acinar cells were binucleated. There was also an age‐related increase in pigment granules throughout the gland. These membrane bound granules consisted of a lipid droplet and an associated dense cap which had a granular matrix and pigment droplets. The lead capture method for acid phosphatase activity demonstrated that activity was associated with the granular matrix of the dense cap. These results were correlated with the age‐related increase in acid phosphatase activity as determined by colorimetric procedures.There was an age‐related increase in the number of cells characterized by small secretory granules. These cells were found as part of the intercalated ducts or at the junction of the duct with the acini. Oncocytes were also found as part of the parenchyma of the aged submandibular gland. These cells were characterized by the pleomorphic mitochondria that fill their cytoplasm. Occasionally, cells that possessed extraordinary numbers of mitochondria and small secretory granules were also observed.The determinations of total DNA and RNA revealed and age‐related decrease in RNA while there was no significant change in the concentration of DNA.
Postnatal development of the oviduct of intact and ovariectomized rabbits
Authors: Hafez E. S. E. , Kodituwakku G. E. 
Published: February 2005

AbstractThe length of the oviduct, the thickness of its wall, and the height of its mucosal epithelium and cilia were measured in (a) 0‐, 2‐, 4‐ and six‐month‐old rabbits, (b) rabbits ovariectomized at birth and (c) ovariectomized, estrogen‐treated rabbits. The length and external diameter of the oviduct increased progressively until four months of age, after which their rates of increase declined. The thickness of the oviductal wall at the uterotubal junction was twice as large as that of the isthmus at two months of age and six times as large at four and six months of age. The height of the mucosal epithelium in the fimbriae was less than that in other oviductal segments at birth, but exceeded that in other segments at six months of age. Ciliated cells and motile cilia were absent 24 hours after birth; they were first observed two months after birth. The cilia of fimbriae were shorter than cilia elsewhere in the oviduct. Neonatal ovariectomy retarded the development of the oviduct and the mesotubarium and caused pyknosis of ciliated and non‐ciliated cells of the oviductal mucosa. Cells with scarcely motile cilia were present five and one‐half months after neonatal ovariectomy.
Morphogenetic studies of the rabbit. XL. Growth gradient interaction and function in morphology
Authors: Sawin P. B. , Hamlet Martha 
Published: February 2005

AbstractIn continuing study of gene and genome interaction as a possible etiological mechanism in normal and abnormal growth and malformation, the ventral spinous processes (VSPs, crural insertions of the diaphragm) were used as additional epigenetic variants to portray differences in the basic gradient growth pattern. Over 700 comparisons of mean differences in number (range or magnitude) and peak (position) of the VSP gradient, in the same populations of strains III, DA, and IIIDa (into which the Da gene had been introduced from strain DA), provided populations of +/+, Da/+ and Da/Da on two different genome backgrounds. They reveal the individual effects on the VSPs of underlying growth processes associated with the Da gene dosage, vertebral border shifts and stillbirths. Both Da and stillbirths demonstrate growth influences which interact additively to reduce the range and shift the peak anteriorly in opposition to those of the border shifts. The growth effects induced by border shifts are in some cases significantly so much greater as to seemingly inhibit or even reverse either the specific gene Da or stillbirth effects. The way that interaction of such growth influences can enhance, suppress or cancel each other and the relation to specific growth gradients and functions is of particular importance to understanding the etiology and growth mechanisms of spontaneous and unexpected exogenously or endogenously induced malformations in non‐isogenic stocks.