428 



Records of the Indian Museum. 



[Vol. XVI, 



The genital gland forms a mass of small round cells situated 

 ventrally and immediately behind the posterior margin of the acet- 

 abulum. In addition to this group of cells there is along the 

 posterior and lateral border a series of five or six large round cells 

 with clear protoplasm and a small granular nucleus. It would seem 

 probable that these large cells represent the rudiments of the testes, 

 while the central mass of small cells represents the rudiments of 

 the ovary. 



The cercariae develop in elongate sausage-shaped sporocysts. 

 In some cases, however, the sporocysts appear to be more or less 

 oval or pyriform. Each sporocyst contains two or three mature 

 cercariae; occasionally some of the cercariae appear to become 

 encysted either in the sporocyst or in the substance of the liver 

 outside. In these cases the cyst is of an elongate oval shape and 

 has a thin clear wall, the cercaria lying within the cyst in a partially 

 extended state and not, as is the case in most encysted forms, 

 curled up into a spherical ball. The cercariae appear to reach the 

 full development within the sporocyst before leaving it to enter the 

 host's liver tissue. The liver of an infected snail is of a yellowish 

 brown colour and has a mottled appearance owing to the sporo- 

 cysts appearing on the surface. 



The host. The cercariae develop in either Planorhis exustus^ 

 Desh. or in a form of Limnaea amygdalum, Troschel, in a tank in 

 Russa Road South, Tollygunge, Calcutta. 



Size. 



Body. 



Tail trunk. 



Furca. 

 Oval sucker. 



Mucin gflands. 



Mucin ducts. 

 Duct openings. 



Germ cells. 



Parthenita. 



Present species. 



90— 196 /x X 50 M- 

 186 — 221 (U X 25 IX. 



7 1 - 96 M- 



32 ^ X in transverse diam, x 

 4.3 M in length. 



5 pairs of pyriform cells with 

 large nuclei and with gra- 

 nular acidophilic cyto- 

 plasm ; the anterior two 

 pairs coarsely granular 

 and the posterior three 

 pairs finely granular. 



Very thick. 



At anterior end of protrusible 

 snout ; capped by five 

 pairs of hollow, piercing 

 spines. 



Clustered mass of cells just 

 behind antabulum along 

 the postero-lateral margin 

 5-6 large round cells with 

 granular nuclei. 



Sporocyst. 



Sell, japonicum. 



100 — 210 X 66 jti. 

 150 ft X 20 ;u. 



75 M. 



33 n in transverse diam. X 54 

 fx in length. 



5 pairs of pyriform cells with 

 large nuclei and granular 

 acidophilic cytoplasm. Cort 

 makes no mention of any 

 difference in the various 

 cells. 



Very thick. 



At anterior end of protrusible 

 snout ; capped by five pairs 

 of hollow, piercing spines. 



Clustered mass of cells just 

 behind antabulum. 



Sporocyst. 



In the accompanying table, adapted from Faust [I.e., p. 167), 

 I have given the main characters of the present type and of the cer- 

 caria of Schistosoma japonicum in parallel columns. The present 

 form appears to be very slightly smaller as regards the body and 

 a trifle longer in the tail, but owing to the degree of contractility 



