1917.] NATURAL SCIENCES OF PHILADELPHIA. 193 



irregular ribs which do not affect the margin (and are sometimes 

 wanting). Cardinal area oblique; no crenulation of the margins 

 near the hinge or elsewhere. Upper valve with the beak oblique, 

 cardinal area rather long. 



Greatest length (alt.) 33, width 27 mm. 



Type No. 2633, A. N. S. P., from between Las Caobas and Thom- 

 onde, Haiti, collected by Mr. Lloyd B. Smith, 1914. 



Anomia gabbi n. sp. 



Anomia ephippium Linn., Gabb. 



Very similar to the European A. ephippium. Externally the 

 convex value has a coarse sculpture of radial ribs, with radial 

 riblets and striae in the intervals. The byssal impressions are dis- 

 tinctly but not deeply impressed, but sufficiently to be readily seen 

 or felt. Major impression somewhat square; minor impression close 

 below it and not greatly smaller. Adductor inpression alongside 

 the minor byssal scar, not lower down. The shell is orbicular, and 

 somewhat stronger than A. ephippium or A. simplex. Alt. 48 mm. 



T>T3e No. 2642, A. N. S. P. 



There is the fragment of another valve, having the external sculp- 

 ture less uneven though equally coarse. 



Fecten plurinominis n. sp. 



Peden oxygonum Sby., Gabb, Trans. Amer. Philos. Soc, XV, 1873, p. 256. 



Not of Sowerby. 

 Peden thetidis Sowerby, Dall, Trans. Wagn. Inst., Ill, p. 714. Not of 



Sowerby. 



In this scallop there are 19 rounded ribs a little wider than their 

 intervals, over ribs and intervals there are weak radial cords bearing 

 thin scales, near the edge of the left valve there are three of these 

 scaly cords upon each rib and three in each interval. Submargins 

 and ears with numerous small ribs. Ctenolium is rather long. The 

 right valve is slightly more convex than the left. 



Length and alt. 31 mm. 



Type No. 3236, A. N. S. P. 



This species resembles the recent P. fuscopurpurea Conrad in 

 sculpture, but the ribs are not so strong and the ears are much 

 smaller. In our opinion it cannot be either P. oxygonum or P. 

 thetidis of Sowerby. Whether it is specifically separable from 

 several forms found in the Canal Zone and Costa Rica is uncertain, 

 but there are various differences which indicate at least racial dis- 

 tinction. Typical specimens occur in some abundance in the Bowden 

 bed also. 



