482 PROCEEDINGS OF THE ACADEMY OP 



6. Valves elongate-cuneiform. 

 Hiatus, equalling the whole length of the shell, apertissima, impress a, 

 lamellosa, Riippellii, spathulata, Stimpsonii, 

 t enera. 

 " nearly the entire length of the shell, cucullata, difficilis, 



interrupta. 

 " about two-thirds the length of the shell, indis tine ta, Phi lip p i- 

 nensis. 



13. R. apertissima, Deshayes, sp. 



Gastrochaena apertissima, Deshayes, Zool. Proc. p. 326, 1854. 

 Rocellaria apertissima, H. and A. Adams, Genera, ii. p. 336, 1856. 



Description. " R. testa elongata, cuneiformi, infiata, tenui, fragili, per 

 totam altitudinem testa antice inferneque hiantissima, alba, tenui, pellucida, 

 antice brevissima, margine inferiore fere recto, posteriore obtuso, convexo, 

 superiore paulo obliquo ; valvis tenuissime striatis, striis in latere antico 

 transversalibus, in medio secundum lineam obliquam fractis, in area superiore 

 armatis, pluribus majoribus, subaequidistantibus ; ligamento angusto, elongato, 

 nigrescente. ' ' Deshayes. 



Hab. Philippines. Coll. Cuming. 



14. R. cucullata, Deshayes, sp. 



Gastrochaena cucullata, Deshayes, Zool. Proc. p. 329, 1854. 

 Rocellaria cucullata, H. and A. Adams, Genera, ii. p. 336, 1856. 



Description. " R. testa, elongato- cuneiformi, tenui, alba, fragili, subcretacea, 

 extremitate antica brevissima, postica compressa, dilatata, spathuliformi, 

 antice inferneque oblique hiante, apertura lateraliter coarctata, fere totam 

 longitudinem testae aequante, latere antico angusto, incumbente, cucullato ; 

 valvis extus in tres areas divisis, prima antica obsolete striata, mediana. 

 latiore, irregulariter arcuatim striato-rugosa, tertia circa, ligamentum angus- 

 tiore, laevigata ; umbonibus tumidulis, terminalibus ; ligamento satis promi- 

 nulo, elongato, fusco." Deshayes. 



Hab. West Indies. Coll. Cuming. 



15. R. difficilis, Deshayes, sp. 



Gastrochaena difficilis, Deshayes, Zool. Proc. Lond. p. 328, 1854. 

 Rocellaria difficilis, H. and A. Adams, Genera, ii. p. 336, 1856. 

 Description. " R. testa elongato-transversa., ovata, cuneiformi, compres- 

 siuscula, oblique longe hiante, hiatu ovato-oblongo, inferne attenuato, fere 

 totam longitudinem testae aequante ; valvis trapezoidalibus, tenue striatis ; 

 striis tenuissimis, erectis, angustisshnis, in latere antico con ertioribus ; um- 

 bonibus minimis ; latere antico brevissimo, recto ; ligamento elongato, rufo, 

 angusto." Deshayes. 



Hab. Western India. Coll. Cuming. 



16. R. impress a, Deshayes, sp. 



Gastrochaena impressa, Deshayes, Zool. Proc. p. 327, 1854. 

 Rocellaria impressa, H. and A. Adams, Genera, ii. p. 336, 1856. 



Description. " R. testa elongato-cuneiformi, subovata, infiata, antice in- 

 ferneque amplissime aperta ; hiatu totam longitudinem testae aequante, mar- 

 gine lateraliter oblique arcuato, antice angusto ; valvis tenuibus, subtrape- 

 zoidalibus, in medio sulco vix impresso bipartitis, parte antica tenue trans- 

 versim striata, striis in sulco subfractis, parte postica arcuatim et irregulariter 

 sulcato-striata, in latere postico striis oblique ascendentibus ; umbonibus 

 tumidulis, postice obtuse subangulatis, fere terminalibus ; ligamento angus- 

 tissime, elongato, partim immerso." Deshayes. 



Sab. ? Coll. Cuming. 



17. R. indis tin eta, Deshayes, sp. 



Gastrochaena indistincta, Deshayes, Zool. Proc. p. 328, 1854. 



[Dec. 



