iqiq.] N. Annandale & B. Prashad : Gangetic Delta Molluscs. 257 



is crawling. The eyes are visible as small black spots at the base 

 of the tentacles. 



The upper jaw, which is very conspicuous in the living animal, 

 is fully cornified and lunate in form; there is a broad transverse 

 thickened median region, the anterior and posterior regions being 

 almost membranous. The radula is narrowly tongue-shaped (fig. 

 ya), and bears about 60 transverse rows of teeth ; these rows are 

 practically straight. There are about 27 longitudinal rows ; the 

 dental formula being 7-6-i"67. The central tooth (fig. yh) is 

 minute, with a single cusp, which is nearly symmetrical and ob- 



a. 



h. 



Text-fig. 7. — Radula of Auricula transluceiis, sp. nov. 

 {a) Radula as a whole. (6) Radular teeth further enlarged. 



scurely trilobed. The laterals are similar but much larger, and 

 the marginals differ from the laterals in having the cusps narrower, 

 simpler and directed somewhat inwards. 



Type specimen : M ^-^ " in the collection of the Zoological 

 vSurvey of India. 



Locality. — A single living specimen of this species was taken 

 in a creek at Basanti in the Gangetic Delta. In the collection 

 of the Zoological Survey there are also a number of specimens from 

 Port Canning which had hitherto been confused with A. gangetica. 



The shell resembles that of A. socoirana, ^Smith, in sculpture 

 and texture, and that of A. layardi, H. Adams, in shape. 



