36
Scientific Memoirs by
0.056mm. in female ; 0.44mm. in male. Head usually bent down, often into the
form of a hook. Papillae six, of which two are dorsal, two ventral, and two lateral
the latter are more obtuse, and are the openings of the lateral canals. Mouth,
terminal, provided with a chitinous armature, consisting of an annular ring, sup-
porting two systems of 24 teeth each (Curtice). My own observations lead me
to believe that the armature is more complex than this, and that there are three
rows of differently-shaped " teeth." The complexity of the object, however, ren-
ders its resolution, even with high powers, a very difficult matter, especially as
the images of the various rows of teeth are further confused by a radiate ribbing
of the chitinous lips, so placed that each rib is opposite a set of " teeth." The
innermost row have a very characteristic bidentate form, while the second are
long and slender, and have the form of a linear-lanceolate leaf, with the proximal
portions of the margins rolled in towards the midrib.
These fimbriæ, by their convergence, form a sieve, exactly similar to that de-
scribed in the equine sclerostomes, and, external to them, and corresponding in
position to the trephine circlets of S. equinum and robustum, I make out a
circlet of short teeth, with semi-lunar margins. The circumference of the mouth
is curiously ribbed, the ribs being equal in number and opposite to the tooth
systems, and it is, I think, from confusing the image of this ribbing with the
overlying triphine teeth that this circlet has been overlooked by Dr. Curtice in
his description. Immediately beneath the ring supporting the bidentate teeth
is the triradiate opening of the œsophagus, no chitinous buccal cup intervening, as
is the case in the allied genus Sclerostornum. Neck, not inflated, but provided
with a lapel or cuticular fold, on the ventral aspect, just in front of the ventral cleft ;
the fold continues slightly on the dorsal aspect, Two lateral, narrow, membra-
nous wings begin at this fold, and continue for one-fourth the length of the worm.
The two lateral opposite papilla are in these wings, at the level of the first third
of the œsophagus. The pair of unicellular neck glands (lemniscus) unite into
a common duct and empty at the ventral cleft, situate beneath the median fold.
Male, about three-fourths the length of the female. Bursa can, with difficulty,
be spread without tearing. It is slightly prolonged dorsally, but notched in the
middle line so as to indicate a primarily billowed arrangement ; ventral cleft shallow.
Costæ symmetrical, the ventral slightly separated ; the dorsobateral forms with its
fellow and the dorsal pair a group ; dorsal rib bifid ; the divisions widely separate
at free ends. Spicula two ; subulate, bordered by a very narrow membrane ; the
chitinous cylinder is apparently fenestrated. At either side of the genital aperture
are two knobbed papillæ. Female, relatively stouter ; vulva just in front of anus,
which is close to the mucronate tail ; usually covered by a brown crust, consisting
of ova glued together by mucus ; reproductive organs in two symmetrical sets
anteriorly directed, except a small portion of one which loops backwards in front
of the anus, Uteri caudally placed ; can be followed to ovaries, which continue
forwards to œsophagus, below which they are reflected to form a loop, reaching