49 



antice hiantissimil, hiatu subcordiformi, lato, obliquo, et fere totam altitu- 

 dinem testae aequante ; valvis trapezoidalibus, tenuissime striatis, striis in 

 latere antico tenuissimus, appressis, in medio distantioribus, erectis, sub- 

 lamellosis ; latere postico obtuso, superne in sutura cristato ; umbonibus 

 tumidis, postice" depressiusculis, latere antico brevi, recto ; sinu pallii parum 

 profumlo, apioe acuto, triangulari, subaequilaterali." — Deshayes. 

 Hub. ? Coll. Cuming. 



10. 11. o va t a,* Sowerby, sp. 



Gastrochaena ovata, Sowerby, Zool. Proc. p. 21, 1834. 



Th. Miiller, Syn. Test. Viv. p. 235, 1836. 

 Hanley, Desc. Cat. p. 10, t. 9, f. 42, 1842. 

 Catlow, Conch. Nomenc. p. 2, 1845. 

 Jay, Catalogue, 4th edif. p. 9, 1850. 

 Carpenter, Mazatl. Shells, Brit. Mus. Cat. p. 15, 1857. 

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

 Description. — " R. testa ovata, albicante, longitudinaliter striata, striis 

 exilibus, lamellosis, formam marginis semper sequentibus ; longitudine lateris 

 antici quintam partem testae aequante. Long. 1-2, lat. 0-7, alt. 0-7 poll." — 

 Sowerby. 



Hah. — In Sinu Panamensi (Isle of Perico) et ad Insulam Platae. Found in 

 spondyli at the Isle of Perico, and in coral rocks, at a depth of seventeen 

 fathoms, at the Island of Plata. Also inhabits St. Thomas Harbor, W. I., 

 (Coll. A. N. S.) and Charleston Bay, S. Carolina! (Coll. Smithsonian Inst.) 



The great difference in the relative length of the anterior and posterior sides 

 will readily distinguish this species from R. brevis. R. dubia has a 

 slight truncation of the posterior margin of the valves, while this species is 

 always rounded posteriorly. The absence of the laminar hinge-plate and the 

 length of the hiatus also separate this shell from both R. dubia and R. 

 hians . 



I have made a very close comparison between specimens from Panama and 

 those from the West Indies and Charleston, without detecting the slightest 

 difference between them. The Charleston specimens were collected by Dr. 

 Wm. Stimpson. 



11. R. pupina, Deshayes, sp. 



Gastrochaena pupina, Deshayes, Proc. Zool. Soc. Lond. p. 326, 1854. 



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

 Description. — " R. vagina crassa, brevi, clavata, transversim articulata, 

 laevigata, nulla corpora aliena agglutinante, in cavitate valvulae affixa. Testa 

 minima, tenui, alba, hyalina, hiantissima, hiatu amplissimo quasi testae per 

 mediam partem resecto, oblique inaequaliter bipartite, coarctata, extremitate 

 postica clausa, obtusa, attenuate ; latere antico satis longo, incumbente, 

 cucullato ; umbonibus prominulis, oblique terminalibus ; valvis laevigatis, 

 postice sutura brevi, carinata ; margine aperturae dorsali, parallelo." — Desh. 

 Hub. — Morton Bay. Coll. Cuming. 



12. R. r u g u 1 o s a , Sowerby, sp. 



Gastrochaena rugulosa, Sowerby, Zool. Proc. Lond. p. 22, 1S34. 

 Th. Miiller, Syn. Test. Viv. p. 235, 1836. 

 Hanley, Desc. Cat. p. 11, 1842. 

 Catlow, Conch. Nomenc. p. 2, 1845. 

 Rocellaria rugulosa, H. & A. Adams, Genera, ii. p. 336, 1856. 

 Description. — " R. testa oblonga, albida, striata, rugulosa, striis anticis 

 marginem hiantem confertis, acutis ; hiatu longissimo. Long. 0-8, lat. - 3, 

 alt. 0-4 poll. "Sowerby. 



Eab.— " Ad Insulas Gallapagos et apud Insulam Lord Hood's dictam." — 

 Sowerby. 



