Invertebrate Gallery of the Indian Museum. 41 



eaten by another vertebrate animal, then the bladder- 

 worm, when it reaches the intestine of the second host, 

 develops into a sexually mature tape-worm such as those 

 exhibited. 



A specimen of a Cysticercus^ or bladder- worm, is shown 

 in Case 46. 



The Cestoda are further represented by three fine spe- 

 cimens of Taenia mediocanellata, which differs from T, 

 solium in being without the coronet of chitinous hooks. 



4. PLATYHELMINTHES NEMERTINA. . 



[(Lflllci5tern SLtiUl-rasij 46]. 



The Nemertina are flat worms, usually of small size, al- 

 though some reach gigantic dimensions, and are for the most 

 part marine : a few, however, live on land. Unfortunately 

 there are no specimens in the Museum collection, and we 

 are compelled for the present to represent the Order by en- 

 larged drawings of Tetrastemma agricola, a Land Nemertine 

 from Bermuda, and of Pelagonemertes rollestoni^2LX\. Oceanic 

 Nemertine, to both of which explanations are attached. 

 The Nemertina are the most highly organized of the 

 Platyhelminthes. 



PHYLUM II OF THE CCELOMATA. 



NEMATHELMINTHES. 



[fficston MaU-fitse 46]. 

 The Nemathehninthes or phylum of Non-segmented 

 Round-worms includes three natural groups: (i) the Ne- 

 matoda or Thread-worms, (2) the Chxtognatha, and {3) 

 the Acanthocephala. The most noticeable external char- 

 acter that they have in common is the elongated cylin- 

 drical body, which is devoid of appendages of any sort 

 and tapers more or less at both ends. The great majority 

 of the N emathelminthes are parasites : they are, however, 

 on a higher level than the PiatyhelmintheSy the body- 

 cavity being distinct. Reproduction is sexual. 



