1861.] dr. t. s. cobbold on cystic entozoa. 93 



3. On Cystic Entozoa. from the Wart-Hog and Red River- 

 Hog. By T. Spencer Cobbold, M.D., F.L.S. 



(Plate XVII.) 



Although it is now no longer doubted by those who have paid 

 special attention to the genetic relations subsisting between the cystic 

 and cestoid Entozoa, that the former are immature conditions of the 

 latter, yet sufficient interest attaches itself to the structure of ob- 

 scure and otherwise interesting larval forms, to induce me to lay 

 before the Society the accompanying observations. 



From the abdomen of the female Wart Hog (Phacochcerus cBthlo- 

 picus) which died in the Society's Menagerie on the 16th Dec. 185!), 

 and was dissected by Dr. Crisp, Mr. Bartlett, myself, and others on 

 the 19th of the same month, I obtained a solitary Cysticercus. This 

 immature cestoid was enclosed in a thick fibrous cyst situated near 

 the region of the caecum, its size, over all, being rather larger than a 

 cricket ball. On removing the Cysticercus from its fibrous investment 

 — the latter having been accidentally ruptured during the process of 

 evisceration — it was found to consist of the following well-marked 

 parts, which may be respectively recognized as the head, neck, body, 

 and caudal vesicle (PI. XVII. fig. 1). The head'(«) is quite visible 

 to the naked eye, and when viewed from above, by the aid of reflected 

 light under a low magnifying power, displays an oblong quadrangular 

 outline, the corners being rounded off by the presence of four pro- 

 minent sucking disks. At the centre there is a projecting rostellum 

 marked by a circle of radiating lines, such as would indicate the 

 existence of a double row of cephalic hooks. These holdfasts (if I 

 may so term them) were not, however, actually present ; but had in 

 all probability fallen off during the degeneration and calcification of 

 the head, which was quite hard and brittle, and under pressure 

 crumbled up into an amorphous granular mass. The head was easily 

 detached from the neck, the calcified suckers retaining their glo- 

 bular form as perfectly as is represented by fig. 2. That part which 

 I have termed the neck (6) is cornucopial in form, and exhibits well- 

 defined transverse striae, which become rather more distinct towards 

 its base. The body (c) is clavate, elongated, comparatively thick at 

 its anterior third, and narrow at the lowermost part, where it is in 

 connexion with the large circular caudal vesicle. The body and 

 the vesicle {d) are each 'd\ inches in length, the greatest breadth of 

 the former being 1 inch, while that of the latter has a transversal 

 measurement equal to its longitude ; they are both hollow, and when 

 removed were partly filled with a pale-yellow transparent fluid ; they 

 do not intercommunicate, yet both exhibit externally the before- 

 mentioned transverse striae. 



From the female Red River Hog (Polanioc/tcenis jisnicil/atits), 

 which died at the Society's Gardens on the I'ith of November, 1860, 

 I obtained on the 16th of the same month five examples of a Cysti- 

 cercus. In the Society's male Red River Hog, which died last 

 February, no Entozoa of any kind were detected. One of the cystic 

 worms just mentioned occupied a cyst in the liver, the other four 



