192l] NATURAL SCIENCES OF PHILADELPHIA. 423 



of which every second one rises lamina-hke at the anterior end. The 

 liinule is quite small, marked by a rather weak impressed line. The 

 pallial sinus is horizontal, rounded at the end, and reaches beyond 

 the middle of the length. 



Length 25.5, alt. 22, semidiameter 7.2 mm. 



Type is no. 2776 A. N. S. P., a left valve. A series of smaller 

 valves is contained in no. 2775. 



This shell is shorter and more acutely sculptured than P. concin- 

 nus Sowb. 



Cytherea (Antigona) tarquinia (Dall) 



Venus magnifica Hanley, Gabb, Tr. Amer. Philos. Soc. xv, p. 259. 



Venus tarquinia Dall, Trans. Wagn. Inst., iii, p. 1194, pi. 38, fig. 2. (Ballast 



Point, Florida). 

 Cytherea tarquinia Dall, t. c. p. 1274. 

 Antigona tarquinia Dall, U. S. Nat. Mus., 90, p. 147. 



Fine specimens, up to a length of 77 mm. It is probably ances- 

 tral to the recent C. listen, in which the concentric sculpture is much 

 more strongly developed. 



While Cytherea magnifica is related, it differs by the wider, flatter 

 radial striae. 



Chione (Lirophora) paphia (L.) 



Chionc pappia Linn., Gabb, Trans. Amer. Philos. Soc, xv, 1873, p. 249. 

 ? Chibne (Lirophora) hendersonii Dall, Trans. Wagn. Inst., iii, p. 1295. 



Five valves, no. 2669. We cannot distinguish them from the re- 

 cent species. Numerous specimens from Jamaica (no. 11041), which 

 are apparently referable to C. hendersonii Dall, do not seem to be 

 specifically distinct. 



Chione santodomingensis Pils. and Johns. Plate XLVII, figs, l, 2. 

 Proc. A. N. 8. Phila. 1917, p. 199. 



Chione socia Pils. and Johns. Plate XLVII, figs. 12, 13. 



Proc. A. N. S. Phila. 1917, p. 199. 



Chione primigenia Pils. and Johns. Plate XLVII, flgs. 6, 7. 



Proc. A. N. S. Phila. 1917, p. 199. 



Chione guppyana Gabb. Plate XLVII, flgs. 3, 4, 5. 



Chione guppyana Gabb, Trans. Amer. Philos. Soc, xv, 1873, p. 249. 



A peculiarity of this species is that the ventral faces of some or all 

 of the concentric lamellae have about twice as many ribs as there 

 are in the intervals. This is shown in the detail photographed in 

 fig. 4. It is a rather plump, rounded shell, related to C. ivoodwardi 

 Guppy. 



Length .31.3, alt. 30 mm. Type no. 2773. 

 . Length 32.5, alt. 29, diam. 22.3 mm. 



