BY C. HEDLEY. 687 



This dentition bears out the relationship claimed on shell 

 characters with western species. Compare Godwin-Austen's 

 account of the anatomy of M. rinkii from the Nicobars (Land 

 and F. W. Moll, of India, p. 12, pi. in.). 



Helicarion musgravei, Hedley. 



Jaw (pi. xxxvni., fig. 9) short, wide, with a stout blunt median 

 projection, ends emarginate. 



Radnla (pi. xli., fig. 30) oval, three times as long as broad, 

 stained brown anteriorly ; formula 128 rows of 45 : 18 : 1 : 18 : 45; 

 rachidian bearing a slender lanceolate median cusp surpassing its 

 basal plate and two well developed accessory cusps ; laterals long, 

 narrow, with a slender median cusp, which becomes longer and 

 more inclined as the ranks retreat, proximal accessory cusp rudi- 

 mentary, distal one well developed ; transitional teeth four or five, 

 marginals much inclined, cusp bicapitate. 



Cristigibba macgregori, Hedley. 



Jaw (pi. xxxviii., fig. 6) boomerang-shaped, smooth, ends trun- 

 cated, no transverse ribs, inferior margin showing traces of denti- 

 culation, centre of the jaw closely longitudinally wrinkled. 



Radula (pi. xxxix., fig. 12) strap-shaped, twice as long as wide ; 

 formula 110 rows of 26 : 20 : 1 : 20 : 26 ; rachidian two-thirds 

 the size of the immediate laterals, with a stout square-headed 

 cusp extending along three-fourths of the narrow basal plate ; 

 laterals also square-headed, very slightly inclined, alate angle of 

 basal plate scarcely produced ; marginals tricuspid. 



Chloritis leei, Cox. 



Jaw (pi. xxxix., fig. 15) arched, crossed by about eight stout 

 flat-topped ribs, which denticulate either margin and are divided 

 by narrow interstices, ends smooth, truncate. — 



Radula (pi. xxxix., fig. 13) strap-shaped, three times as long as 

 broad, rows nearly straight; formula 167 rows of 40 : 17 : 1 : 17 : 40; 

 rachidian unicuspidate, stout, linguiform, two-thirds the length of 



