OF SOUTHERN INDIA. 21 



opposite valves. Above these teeth there is a small cartilage lodged. I have seen 

 only large specimens of Conrad's type Farapholas Califo7micus, and these do not 

 show any teeth, but a cartilage below the beaks ; the shells of the pholadinm 

 change, however, so much with age, that I could not feel certain in proposing a new 

 generic name for our shells unless I had the opportunity of examining young and 

 fresh specimens of the above-mentioned type species. 



10. Pholadidea, Turton, 1819, (H. and A. Adams, Gen. ii, p. 328). Shell 

 very similar to Martesia, the two dorsal accessory valves are smaller than in 

 Farapholas ; the posterior end is enlarged into a cup-shaped appendage protecting 

 the siphons. 



Tryon in his last review of the JProladid^ in American Journ. of Conch, 

 (vol. iii, 1867, part 3), quotes the following sub-genera of this genus; Satasia, 

 Gray, Talonella^ Gray, Netastomella, Carpenter. The differences of these from the 

 type genus appear to be of little importance. I shall only refer to the last one ; of 

 the first PA. melanura^ Sow., of the second Fh. tridens, Sow., are considered as types. 



10a. Netastomella^ Carpenter, 1865, (Proc. Zool. Soc, p. 202,) is based upon 

 Fholas Darwi7iii, Sow., the valves of which are posteriorly prolonged into a 

 flattened calcareous cup. It is said to differ from Jouannetia in having both valves 

 equal, and from Fholadidea by the calcareous nature of the cup at the posterior 

 end of the shell. 



11. Fenitella, YsilenG., 18?? (Conrad, 1849,- see Tryon's Memoir on the 

 Fholadib^ in Proc. Phil. Acad, for 1862). Shell very similar to that of the 

 previous genus, slightly expanded posteriorly ; one umbonal and two pre-umbonal 

 accessory valves, placed side by side, are present. 



12. Talona, Gray, 1840, (H. and A. Adams, Gen. ii, p. 329). Shell in form 

 resembling Fholadidea ; anterior hiatus open, very small ; pre-umbonal margins of 

 the valves refiexed; two small umbonal plates side by side; posterior end enlarged, 

 cup-shaped, and protected by a pair of siphonal valves. 



13. Navea, Gray, 1851, (ibid., p. 328). Shell small, sub-ovate; one small 

 post-umbonal accessory plate ; anterior hiatus widely open. 



14. Barnea, Leach, 1826, (ibid., p. 326). Shell elongately ovate; one 

 narrow and long umbonal accessory plate ; umbonal processes thin, refiexed. There 

 are two slightly different types of shells referred to this genus by Tryon. The one 

 kind, like J5. Candida, L., has the margins of the valves rounded, and the anterior 

 hiatus is long and narrow ; these shells are considered to be typical Barnece, 



14^. The other form, represented by B, parva, L., has the antero-ventral 

 margin insinuated, and the anterior hiatus is short and wide. Por this last the 

 sub-generic name Anchofhasa, Leach, has been adopted. 



146. Mbnothyra, Tryon, 1862, (Proc. Phil. Acad.) may be considered as a 

 third form of the same general type ; it only differs from typical Barnea by having 

 the umbonal plate larger, cuneiform, and the umbonal processes cellular. Fholas 



