X. STUDIES IN INDIAN HELMINTHO- 

 LOG Y, No. II. 



By F. H. Stewart, M.A., D.Sc, M.B., CapL, I.M.S., 



Hon. Assistant, Indian Museum. 



THE ANATOMY OF POLYSTOMUM KACHUGAE, sv. Nov., 

 WITH NOTES ON THE GENUS POLYSTOMUM. 



Polystomum kachugae, sp. n. 

 (Plates XX vi — xxix.) 



Two specimens were found in the urinary- bladder of a water 

 tortoise [Kachuga lineata- Gra)^ at Lucknow. They were fixed 

 in boiling alcohol, 70%: one specimen was stained with borax- 

 carmine and mounted entire, the other after being stained with 

 the same stain and sketched in oil of cloves was cut into serial 

 sections. I am indebted to my friend Major Walton, I. M.S., for 

 the opportunity of obtaining the specimens at the Medical College, 

 Lucknow, and to Dr. Annandale for the identification of the 

 tortoise. 



The body of this new Polystome measures 6-5 mm. in length 

 and 2 mm. ni breadth at the level of greatest breadth. It is 

 bluntly pointed at the head, becoming broader in the first 2 mm ; 

 the second 2 mm. of length correspond with the greatest breadth. 

 There is a slight but sudden narrowing I'S mm. from the posterior 

 extremity. The cotylophore is 1-33 mm. in breadth, the part of 

 the body immediately preceding it is i"3 mm. 



The mouth is subterminal and flattened, of crescent shape 

 when looked at from the ventral surface. The dorsal lip projects 

 downward into the mouth (PI. xxvii, fig. 2). Eye spots are not 

 present. Four longitudinal lines of nuclei occur on the ventral 

 surface, outlining the sheaths of the ventral nerve cords. The 

 aperture of the genital atrium is situated i'i5 mm. from the 

 anterior extremity. 



The cotylophore bears six cup-shaped suckers (PL xxvi, fig. i) 

 the largest of which measures -4 mm. in diameter. Each sucker 

 projects freely from the surface. The wall of the organ is seen in 

 sections (PI. xxix, fig. 18) to consist of an outer layer of ectoderm 

 (o.e.), a loose fibrous layer (f.l.), an outer cuticular layer (o.c.l.), 

 a muscular layer (m.l.), an inner cuticular layer (i.cl.), and an 

 inner ectodermal layer (i.e.l.). The cup formed by the outer cuti- 

 cular, muscular, and inner cuticular layers is perforated at the base, 

 retractor muscles being attached to the margins of the perforations. 



