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116 H. CHARLTON BASTIAN ON THE STRUCTURE AND 
part of its course. A similar arrangement of mesenteric processes is said to be met with 
in Strongylus gigas. For about the first inch the peritoneal sheath is maintained in the 
centre of the body by means of the glandular processes with which it is in contact on all 
sides. It varies much in size in different parts of its course, though the average breadth 
is about +;th of an inch. It is less than this just behind the mouth, and for the last 
half-inch also tapers to about 41;th of an inch in diameter, which is the same size 
as that surrounding the commencement of the intestine. At the termination of the 
cesophagus there is a distinct constriction of the sheath (Pl. XXII. fig. 332); and 
although this undergoes no change in size, the contained tube does. 
The whole of this cesophageal sheath is lined with a layer of muscular tissue composed 
of longitudinal intereommunicating fasciculi, the separate fibres of which are about 
Teo00th of an inch in breadth. 
The intestine at its commencement is twice or three times as broad as the cesophagus, 
being 41sth of an inch in diameter (Pl. XXII. fig. 33 2); it has much thinner walls, and, 
as well as its containing sheath, continues of a nearly uniform size throughout its whole 
extent, only tapering somewhat towards the posterior extremity, where the intestinal tube 
is 414nd, and its sheath sth of an inch in diameter. 
'The whole intestinal eanal is surrounded, between it and its sheath, by a collection of 
various-sized, highly refracting fat-cells, which have been before alluded to, and which 
may be considered to have an hepatic function*. These cells commence at the constriction 
between the cesophagus and intestine, and are continued, together with the peritoneal 
sheath, quite to the termination of the intestine (Pl. XXII. fig. 33 4), though Mr. Carter 
supposed that both were absent from the terminal portion, judging from what he had 
seen of the structure of the “ microscopic Filaridze." | 
I quite agree with Carter, that the intestine terminates in the concavity of the tail, 
where it is attached to the middle of the ventral muscle (or rather in the median line 
between the two ventral muscles); and though neither of us has succeeded in satisfactorily 
recognizing an anal aperture in this situation, yet I think there can be little doubt that 
such a minute aperture does exist, more especially after the independent observation of 
Wagnert, who, not knowing where the intestinal canal terminated, observed a minute 
opening precisely in this situation, as shown by his figure. 
Organs of Generation.—The genital apparatus consists of a large, highly organized sac 
or uterus, distended with young Filaric and a little fine granular matter. It occupied the 
whole of the peritoneal cavity in the specimens examined, except from one to two and à 
half inches from the anterior extremity and about a quarter of an inch or less from the 
tail. Both anteriorly and posteriorly, this large sac terminates abruptly in a small tube 
twisted several times round the intestine (Pl. XXII. figs. 34, 35), or forming a knotted 
glandular-looking mass. Each tube is about one inch in length, and the two are in every 
e May they not also be homologous with the peculiar * corpus adiposum” described by Meissner (Zeitsch. für 
Wissen. Zoologie, Bd. v. 1854) in connexion with the alimentary sheath of Mermis albicans? 
In the portions of the alimentary canal of the specimens examined which had been compressed by the genital tube, 
q E indistinet trace of these cells could be detected (Pl. XXII. fig. 33 3). 
oc. cit, 
