52 proceedings of the geological society. [may 16, 



Bulla paupercula. 



Testa ovato-oblonga, mediane subcoarctata, Isevis, antice transversim striata, labio 

 columellari antice incrassato. 



Carditjm Haitense. Pl. X. fig. 11. 



Testa oblique subovata gibbosa, radiatim eostata, lateribus brevibus, costis qua- 

 tuor et viginti, quadratis, graniferis, interstitiis creberrime rugulosis ; angulo 

 postico rotundato ex umbone ad marginem iuferiorem posticam decurrente. 



Very like C. subovale of Brod. and Sow., but wider, and distin- 

 guished further by the squareness of the ribs. The grains on the 

 ribs constitute another remarkable character, in which this differs 

 from C. subovale. 



Arca Patricia. 



Testa aequivalvis, quadrata, infra rotundata, crassissima, lateribus superne subauri- 

 culatis ; margine inferiori rotundato ; latere postico paululum extenso ; super- 

 ficie radiatim eostata, costellarum lateribus superne angulatis, costellis anticis 

 obsolete granosis ; serie dentium cardinis angusta, postice recurva. 



Distinguished from A. grandis by its form, which is much more 

 rounded at the inferior margin ; by the angularity of its radiating 

 ribs, which are moreover rather more numerous ; and by the narrow- 

 ness of the line formed by the row of hinge-teeth, and the recurved 

 posterior termination of the same row. 



Arca consobrina. Pl. X. fig. 12. 



Testa oblonga, obliqua, aequivalvis, radiatim eostata, lateribus superne angulatis, 

 antico infra rotundato, postico rotundato-angulato ; costis angustis, numerosis, 

 plerumque quadratis, et decussatis, ad basin sulco tenui divisis, posticis fere 

 laevibus, planulatis ; area cardinali latiuscula. 



In general appearance this resembles A. lahiosa ; the cardinal area 

 is, however, much larger, and the ribs, except some of the posterior, 

 are decussated. Judging from a cast, the two valves appear to be 

 equal. 



Pecten Thetidis. 



Testa orbicularis, turaida, radiatim eostata, costarum marginibus quadratis, ad 

 utrumque latus squamuliferis, squamulis minutissimis, interstitiis rugulosis ; 

 auribus insequalibus, radiatim costatis, costellis squamulosis. 



Pecten in^qualis. 



Testa suborbicularis, tumidiuscula, costellis radiantibus 19, rotundatis, laevibus, 

 subdistantibus, superne lineis decussantibus hie illic sparsim notatis ; interstitiis 

 rotundatis, laevibus, sequidistantibus ; alterius valvse costellis angustioribus in- 

 terstitiis latioribus, Isevissimis ; auribus insequalibus, radiatim costellatis. 



Pecten oxygonum. 



Testa suborbicularis, subobliqua, tumida, costellis radiantibus 19, superne acutan- 

 gulis, interstitiisque ajqualibus lineis incrementi concinne decussatis ; auribus 

 insequalibus, laevibus, radiatim costellatis, costellis tenuissimis. 



