NODTJLARIA. 143 



short subtransverse angularly flexuous lines, and elsewhere are 

 broken into short zigzags, or angular dots (like a worn out rasp) ; 

 dorsal and ventral edges subparallel, the latter straightish, a 

 little retuse ; anterior side bluntly biangulated ; umbones eroded, 

 not prominent ; nacre bluish, iridescent in front ; anterior 

 lateral tooth elongated, posterior lateral tooth very short, much 



elevated The primary tooth, in the only valve known to me, 



is a mere callus. 



Long. 18, lat. 32 mm. 



Hob. Assam ; Seebsaugor (Indian Mus. Coll.). 



The dimensions of two specimens in the Indian Museum are : 



1. 2. 



Long 13 12'5 mm. 



Lat 23 22 mm. 



Diam 6'7o 7 mm. 



277. Nodularia (Nodularia) andersoniana (Nevill). 



Unto andersonianus, Nevill, J. A. S. B. xlvi, 1877, p. 40 ; Yunnan 

 Exp. pi. 80, fig. 9. 



Original description : Shell allied to U. pachysoma, Bens., and 

 to some of the varieties of U. cceruleus. Lea. It is easily distin- 

 guished from U. bonneaudi by its more irregular shape, thinner 

 texture, by the acute angulation, greater production posteriorly, 

 and by the more developed sculpture ; a constant character also is 

 the pink colour of the nacre, which in U. bonneaudi is bluish 

 white, this is equally distinct and characteristic in young as in old 

 specimens. 



Long. 15-5, lat. 32, diam. 11-75 mm. 



Hob. Myadong, Burma. 



278. Nodularia (Nodularia) theobaldi, Preston. 



Nodularia (Nodularia) theobaldi, Preston, Rec. lud. Mus. Calcutta, 

 vii, 1912, p. 292. 



Orif/inal description: Shell ovately rectangular, very slightly 

 curved, gaping anteriorly, moderately solid, concentrically striate, 

 covered with a dark olivaceous periostracum ; umbones small, 

 not prominent ; dorsal margin somewhat arched, ventral margin 

 slightly excavated in the median region, otherwise straight ; 

 anterior side slightly produced and somewhat sharply rounded ; 

 posterior side very obtusely rostrate, steeply sloping above, then 

 sharply rounded and again sloping inwards below ; cardinal teeth 

 in right valve roughly triangular, jagged, somewhat inwardly pro- 

 jecting, fitting between two teeth in the left valve, which are 

 roughened and of which the anterior is rather broad and massive ; 

 lateral teeth in both valves elongate and nearly straight ; anterior 



