246 



Records of the Indian Museum. 



[Vol. X, 



in glycerine-jelly-formalin. (2) Indian Museum No. ZEV. 6195/7: 

 from Spongilla sp., Pigeon Island, Chilka Lake, Orissa. 25-1-T4. 

 Two immature specimens, mounted in glycerine-jelly-formalin. 



The measurements will be found in Table I 



The head is marked off from the body by a slight but abrupt 

 increase in breadth at the level of the posterior end of the buccal 

 capsule. The maximum breadth is situated at the middle of the 

 body and decreases very slightly and gradually to the anterior 

 end ; in the posterior third there is also a slight but gradual 

 decrease to the anus ; tail conical from the anus to the commence- 

 ment of the caudal appendage. Vulva very slightly prominent, 

 close to the middle of the body. 



The head bears six lips, mobile as in 0. indicus. In the four 

 specimens under consideration at present the lips are closed in 

 over the mouth. The lips are situated — two laterally, two sub- 

 dorsally and two subventrally. Each lip bears a minute papilla 

 on the outer surface. Bristles do not occur on the head. Lateral 

 organs, oval in shape, lying transversely, distant o'Oig mm. from 

 the anterior extremity, length 0-005 mm., breadth 0*0085 mm., 

 anterior border of the oval slightly flattened. Buccal capsule 

 cylindrical with a large right subventral tooth, and two smaller 

 teeth, one dorsal, one left lateral as in 0. indicus, v. Linst. 



No rings on the cuticle. Hairs occur irregularly in the 

 oesophageal region, one marked row in each lateral line in this 

 region. No bristles at the vulva or anus. 



Tail simply conical from the anus to the commencement of 

 the caudal appendage, differing therefore from 0. fuscus, Bast, 

 and 0. indicus, v. Linst. {vide Pis. xxxi, xxxii, figs. 18, 19, 20). 

 The caudal appendage is uniform in diameter and curves ventrally. 

 A very slight annular constriction at the junction of tail and caudal 

 appendage, A single caudal gland tube in front of the caudal 

 appendage. 



Oesophagus simple club-shaped, coarsely muscular. Intestine 

 with many black globules. 



Nerve ring not observed. Many cells enclosing the oeso- 

 phagus. No ocelli. 



Female gonads of the usual double type, a shell gland inter- 

 poses between ovarian caecum and uterus as in 0. vulgaris, Bast. 



Contrasting 



Total length . . . 

 Head and body 



Shape of tail 

 Colour 



(i) O.fuscus, Bast. 



7 mm. 



Separated by a very faint 

 increase of breadth at 

 end of mouth capsule. 



Fig. 20. 

 Brown. 



(2) O. indicus, v.L. 



2'2 mm. 



Not separated. 

 Fig-. 16. ... 



Fig. 19. 

 Grey. 



(3) 0. chilkensis. 



2"2 mm. 

 Separated by 



marked increase 



of breadth. 

 Fig. 17. 

 Fig. 18. 

 Brown. 



Cobb's Formula, 9 



1-37— X — 2-59- 



>74— r( 



1-37— x—ivg — 45'9 —95- 



