2i4 Bulletin 29 378 



in our shell its termination is defined by a fine but sharp carina- 

 tion extending from the umbonal region to the base, the posterior 

 slope of this carination forming a smooth band marked only at 

 frequent intervals by fine, oblique raised growth-striae; (3) the 

 posterior region is very slightly undulate in diverse/, but markedly 

 so in our fossil, there being two sulci with a fold between ; (4) 

 the sculpture over the central part of our shell is much finer and 

 more delicate, consisting of fine radial and concentric lines ; and 

 anteriorly the concentric lines are sharper than in diversa. 

 Length 24, approximate altitude 21, diameter 18 mm. 



Our single specimen though imperfect has seemed worth de- 

 scribing as it is the first Protocardia ever found in the Dominican 

 blue clays. 



Locality. — (Exp'd' 16) Zone G, Rio Gurabo at L,os Que- 

 mados (very rare). 



Protocardia islahispaniolce, n. sp" 

 Plate 36, Figure 1 1 



Shell markedly resembling the recent deep sea Antillean P. 

 peramabilis Dall and, to a less degree, the allied Bowden P. 

 jamaicensis Dall ; but nearly twice the size of the first and four 

 times that of the second, and more excavated posteriorly than 

 either. Posterior sculpture extending over more than a third of 

 the shell, terminated by a slightly thicker radiating riblet and 

 consisting of very narrow riblets, three to every millemeter, alter- 

 nating with wider interspaces which are either transversely or 

 obliquely cross-barred with fine lamellae, those obliquely barred 

 intervening between one or generally two straight-barred spaces. 

 For a distance of about five millemeters from the posterior mar- 

 gin the riblets cease and the surface is smooth except for three 

 rather distant impressed, punctate lines. Near the anterior bor- 

 der of the posterior sculpture several rows of very minute 

 prickles remain, evidently the remnants of many which once 

 ornamented the shell and have been abraded. The few which 

 remain all arise from the obliquely-barred i?iterspaces. 'The anter- 



