ENTOZOA. 



67 



-26 



the Bothriocephalus latus, and which may be regarded as the types 

 of the two leading genera of the order Cestoidea. 



The Tcenia solium is that which is most likely to fall 

 under the notice of the British medical practitioner. It 

 is the common species of tapeworm developed in the in- 

 testines of the natives of Great Britain ; and it is almost 

 equally peculiar to the Dutch and Germans. The Swiss 

 and Russians are as exclusively infested by the Bothrio- 

 cephalus latus. In the city of Dantzig, it has been re- 

 marked, that only the TcBnia solium occurs ; while at 

 Konigsberg, which borders upon Russia, the Bothrio- 

 cephalus latus prevails. The inhabitants of the French 

 provinces adjoining Switzerland are occasionally infested 

 with both kinds of tapeworm. The natives of north Abys- 

 sinia are very subject to the Tcenia solium, as are also the 

 Hottentots of South Africa. Such facts as to the prevalent 

 species of tapeworm in different parts of the world, if 

 duly collected by medical travellers, would form a body of 

 evidence not only of elminthological but of ethnological 

 interest. In the Bothriocephalus latus of some parts of 

 central Europe and of Switzerland we may perceive an 

 indication of the course of those north-eastern hordes which 

 contributed to the subversion of the Roman Empire ; and 

 the Tcenia solium affords perhaps analogous evidence of 

 the stream of population from the sources of the Nile southward 

 to the Cape. 



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 an- 

 terior part {fig. 26.), 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. It commences by a central rostellum, which 

 is surrounded by a double circle of small recurved 

 hooks {Jig. 27, a), occasionally shed in old individuals. 

 Behind these are four suctorious cavities {Jig> 27, b), 

 by which the head is firmly attached to the intestinal 

 membrane. The anterior segments are feebly repre- 

 sented by transverse rugae ; the succeeding ones are 

 subquadrate, and as broad as long. They then become 

 sensibly longer, narrower anteriorly, thicker and broader at the pos- 

 terior margin, which slightly overlaps the succeeding joint. The 

 last series of segments are sometimes twice or three times as long 



F 2 



Head and 

 neck, Taenia 

 solium. 



Tfinia solium. 



