1921.I B. Prashad : Notes on LaineUihranchs. 113 



and V. cochinensis. As stated already he later describ„'d a new 

 species from the Cochin backwaters as V. delicatula I have 

 examined the types of this species and find that it i^ based on 

 very young shells ; this is discu=!sed fully further on. 



The collections in the Indian Museum have recently been 

 greatly enriched by a large series of specimens of both dry shells 

 and spirit preserved specimens from Travancore backwaters on 

 the Malabar Coast received through the courtes}- of Mr. N. P. 

 Panickkar of the Travancore Fisheries Department. This large 

 collection has rendered it possible to go into the question of the 

 validity of the different species of the genus, and to describe the 

 soft parts of this interesting genus. 



Villorita, Griffith and Pidgeon. 



1SJ5. Cyrena (in p;irt), Clra)', Ann. Philosophy , n.s., l.\, p. 137. 



182^1. Venus (in part). Wood, Index Test. Supplement, pi. ii, fi>f. 14. 



18:54. Villorita. (iriffitli and Pidyeon, Animal Kingdom XII, pi. 



xxxi, HjJ. 5. 



1847. Velorita. Gray, Proc. Zoot. Soc. London .W , |3. 184. 



185V Velorita. Gray. Ann Mag. Nut. Hist., ser. 2, XI, p. .^8. 



1854. Velorita. Oeshayes, Cat. Brit. Mas. Cunchifera TI. p. 241). 



1858. Velorita. .Adams, H. and A., Gen. Rec. Moll. H, p. 449. 



1878. Ve.orita. Sowerb)-, Conch. Icon. XX, p. I, figs. Ira — -c. 



1870. Velorita. Clessin, Cvcladea in M.Trtini-Chemn., Conch. Cah., p. 



1887. Velorita. ^iscller, i1/«;;. Conchyliologie. p. log.^. 



1Q[4. Villorita, Iredale, Proc. Malocol. Soc. London XI, p. 178. 



1915. Velorita, Preston, Faun. Brit. Ind., Freshw. Moll., p. 2119. 



The question regarding the name and the validity of the genus 

 has already been discussed in the introductory part. A detailed 

 description of the genus was given by Fischer and a translation of 

 it in English will be found in Preston's volume. No accurate 

 description of the hinge has so far been published, I have, there- 

 fore, thought it desirable to give a detailed description of the two 

 valves separately. 



Right valve. — Anterior lateral tooth short and thick, nearly 

 straight or only slightly slanting, with its posterior edge cut off at 

 an obtuse angle and having a rather deep groove above it for the 

 fitting in of the elbow-shaped anterior lateral tooth of the left valve ; 

 posterior lateral elongate, about i| times as long as the anterior, 

 somewhat blade like and extending up to the anterior border of the 

 scar of the adductor muscle; of the three cardinal teeth, middle 

 one best developed and the anterior one very small and feeble, all 

 three slanting in an antero-posterior axis. 



Left valve. — Anterior lateral fairly large, elbow-shaped, sep- 

 arated from the margin of the shell by a narrow chink but having 

 a deep groove for the anterior lateral of the right valve, posterior 

 lateral less developed than in the right valve, somewhat curved, 

 arising as a thick ridge out of a cavernous hollow ; of the three 

 cardinal teeth the posterior most is the most feebly developed while 

 the middle is the stoutest. 



