342 



Memoirs of the Indian Museum,. 



[Vol. VII, 



Fig. 73. — Cephalobus seistanensis. Posterior end 

 of male ; lateral view. 



a. p., accessory piece; s.. right spicule. 



and an accessory piece 0*015 mm - long. 

 The only caudal papillae appear to be 

 two small ventral pairs near the extre- 

 mity of the tail. 



The tail of the female is tapering, 

 o - o8 mm. long, and curves towards the 

 dorsal side. The vulva opens at about 

 0-55 mm. from the posterior end, i.e. 

 somewhat behind the middle of the 

 body. The single genital tube runs for- 

 ward for about 0-3 mm., and then doubles 

 upon itself to run straight backward, the 

 blind end of the ovary being situated at 

 about 0-1-0-15 mm. behind the vulva. 

 The uterus, in mature females, never 

 seems to contain more than one fully- 

 Such ova have an unsegmented content and measure 0-045 



formed ovum at a time, 



X 0-025 mm - 



The relative dimensions of this species, expressed according 

 to the formula of de Man, would be somewhat as follows : a = 38- 

 40-85 ; ^^4-75-5-S ; y = 19 in male, 17'8 in female. 



Genus Monhysterides, nov. 

 Monhysterides piscicola, sp. nov. 



(Figs. 74, 75.) 



Host: Mahseer (Barbus tor). Locality: Torsa 

 River, Falakata, Eastern Bengal. 



This is a very small form, the male measuring 

 3-5-4-0 mm. in length, the female 3-7-4-4 mm. The 

 maximum thickness is 0-15-0-2 mm. The body is 

 slender and tapering towards each extremity, the mid- 

 dle region being relatively stout. The diameter of 

 the head is 0-03-0-04 mm. The cuticular striation is 

 exceedingly fine. Owing to the very small size of the 

 head the characters of the mouth are difficult to 

 determine. It appears to be surrounded by six small 

 nodules, two of which are probably lateral, two sub- 

 dorsal and two subventral. There are indications of 

 minute papillae near their bases. The oesophagus 

 consists of a short anterior portion which is transparent 

 and purely muscular, about 02 mm. long, and a longer 

 posterior portion which is partly glandular and partly 

 muscular, and is swollen behind. This portion may 



\—0es.b. 



Fig. 74. — Monhysterides pisci- 

 cola. Anterior end of female ; lat- 

 eral view. 



e., excretory pore; oes.b. oesoph- 

 ageal bulb. 



