48 



LECTURE IV 



condensed bag of cellular tissue around it. The cysts are oval, and 

 generally about half an inch in length. The most common hydatid 

 in the ox and other ruminants, is a large species of the present genus, 

 called Cysticercus tenuicollis. All these Cysticerci manifest their 

 affinity with the Cestoidea by the organisation of their head. A 

 species not uncommon in cysts in the liver of the rat and other 

 rodents, completes the transition to the Cestoidea, by having the 

 terminal bladder of small relative size, and the body 

 of great length, and divided into joints or segments. 



I proceed next to consider the organisation of the 

 tapeworms, as the Cestoidean entozoa are commonly 

 termed ; and for this purpose I shall select the two 

 species which infest the human intestines, namely, the 

 Tcenia solium and the Bothriocephcdus latus, and 

 which may be regarded as the types of the two lead- 

 ing genera of the order. 



The TcEnia solium is the only species which is 

 likely to fall under the notice of the British medical 

 practitioner. It appears to be the only species of 

 tapeworm developed in the intestines of the natives 

 of Great Britain ; and it is equally peculiar to the 

 Dutch and Germans, The Swiss and Russians are 

 as exclusively infested by the Bothriocephalus latus. 

 In the city of Dantzig, it has been remarked, that 

 only the TcEnia solium occurs ; while at Konigsberg, 

 which borders upon Russia, the Bothriocephalus latus 

 prevails. The inhabitants of the French provinces 

 adjoining Switzerland are infested with both species. 

 The Tcenia solium attains the length of ten feet 

 and upwards : it has been observed to extend from the 

 pylorus to within seven inches of the anus. Its breadth varies from 

 one fourth of a line at its anterior part {Jig. 20.), to three or four lines 

 towards the posterior part of the body, which 

 then again diminishes. The head is small, and 

 generally hemispherical, broader than long. The 

 mouth is situated on a central rostellum, which is 

 surrounded by a double circle of small recurved 

 hooks {Jig.^l, a). Behind these are four suc- 

 torious cavities {Jig.2\i b), by which the head is 

 firmly attached to the intestinal membrane. The 

 anterior segments are feebly represented by trans- 

 verse rugae; the succeeding ones are subquadrate, 

 and as broad as long. They then become sen- 



Head and neck, 

 Taenia solium. 



.w>. 



'^] 



d,i 



Taenia solium. 



