10 



DR. W jSJIOOLL and PROF. E. A. MIXCHIN OJT 



only as a narrow fissui^e. It represented the very much reduced 

 vesicle, and separated the main part of the body from the part 

 which was eventually evaginated to form the head of the tape- 

 worm. Internal to this was another layer of loose parenchyma, 

 which at the posterior pole merged into the tissue of the scolex. 

 The latter was extremely small (-075 x -09 mm.). On it there were 

 four small circul;a- suckers (diam. "OSS mm.) and a small unarmed 

 rostellum. 



■ Text-fig. 1. 







Cysticercoid of Si/menolepis diminuta. X 125. 



This description tallied almost exactly with that of Gi'assi and 

 Rovelli (Atti Ace. Gioenia Sc. Nat. Catania, iv. 1892, pp. 31-33, 

 pi. iv. fig. 3). They found a corresponding Cysticercoid in the 

 beetles J-X-is spwiosa and Sccmrus siriatus, in Anisolabis anrmlipes 

 and in the larva of Asopia farinalis. By feeding experiments 

 with Cysticercoids derived from the first of these, they were able 

 to produce infection in a man, and the tapeworm which was 

 recovered wsiii Bymeoiolepis diminuta Rud.( = TcEm« leptocephala 

 Creplin). 



It was recognized that the Cysticercoid from the rat-flea wa& 

 very probably the larva of Hymenolepis dimimita, but that could 

 not be definitely stated without further information, for two 

 other rat -tapeworms {H. relicta Zschokke and IT. horrida 

 v. Linstow) are known, closely resembling H. diminuta and 

 probably possessing larvse almost indistinguishable from that of 

 H. dimirncta. On that account, in order to establish the identity 

 of the Cysticercoid, a series of feeding experiments was undertaken. 



