I9I4-] H. B. Preston : Mollusca from the Chilka Lake. 307 



rounded ; anterior side sloping above, rounded below ; posterior 

 side somewhat abruptl}^ descending, a little produced below; hinge 

 plates massive ; right valve bearing an obsolete anterior, an 

 almost vertical median and a very oblique, posterior, cardinal 

 tooth and an oblique, slightly curved, finely striated lateral ; left 

 valve bearing a rather large and nodule-like anterior, a coarse, 

 erect, triangular, almost vertical median and an oblique, posterior 

 tooth which is also erect and coarse and a broad, striate lateral. 



Long. 46*5, lat. 48"5 mm. 



Hab. — On shore at Satpara, Orissa, probably in a subfossil 

 state (Type) ; on shore near Rambha, Ganjam District, Madras. 



Family UNGUUNIDAE. 



Diplodonta (Felania) annandalei, sp. n. 



(Figs. 20, 2oa-b, p. 308). 



Shell somewhat squarely ovate, not very convex, covered 

 with a thin, very pale straw-coloured periostracum, finely concen- 

 trically striate ; umbones small, but rather prominent ; dorsal 

 margin both anteriorh^ and posteriorly sloping ; ventral margin 

 gently rounded; anterior side sharply rounded above; posterior 

 side little produced, the margin rather abruptly descending in a 

 gentle curve ; right valve bearing a rather oblique, broad, short, 

 anterior cardinal and an oblique, slightly curved, narrowly and 

 deeply bifid posterior, cardinal tooth; left valve bearing a slightly 

 curved, broadly bifid anterior and a very oblique, elongated, 

 posterior, cardinal tooth ; palleal line simple. 



lyong. 6, lat. 7 mm. 



Hab.— Between Barnakuda and Nalbano Isd., Lake Chilka, 

 at a depth of 10 feet. 



Diplodonta (Felania) chilkaensis, sp, n. 

 (Figs. 21, 2ia-b, p. 308). 



Shell orbicular, covered with a yellowish brown periostracum, 

 both valves closely, concentrically striate ; umbones not promi- 

 nent ; dorsal margin a little excavated anteriorly, gently sloping 

 posteriorly ; ventral margin rounded ; anterior side rather ab- 

 ruptly descending ; posterior side rounded ; both valves bearing 

 two cardinal teeth of which the posterior is massive and bifid in the 

 right valve, while the anterior has the same characters in the left; 

 interior of shell pinkish. 



Long. 12, lat. I2'5 mm. 



Hab. — Lake Chilka (Type) {ex coll. Raban) ; Manikpatna, in 

 4 feet. 



