484 PROCEEDINGS OP THE ACADEMY OF 



22. R. spathulata, Deshayes, sp. 



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



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

 Description. " R. testa elongato-angusta, cuneiformi, compressiuscula, 

 tenui, fragili, alba, antice longe hiante, hiatu fere totam longitudinem testae 

 eequante, inferne sensim attenuate ; valvis antice angustis, postice latioribus, 

 spathulatis, irregulariter striatis, striis lateris antici tenuioribus, magis regu- 

 laribus, rectis, in medio rugulosis, arcuatis, insequalibus, umbonibus minimis, 

 acutis, fere terminalibus ; latere antico brevissimo ; ligamento elongato, 

 angusto, fuscescente; sinu pallii angustissimo, acuto, profundissimo, usque 

 umbones versus ascendente." Deshayes. 

 Hab. Philippines, Bohol. Coll. Cuming. 



Stimpsonii, Tryon. 



Description. R. testa elongato-angusta, alba, extremitate antiea 

 brevissima, acuminata ; valvis concentrice dense striatis ; umbonibus 

 proininulis, fere terminalibus ; hiatu anguste-elongata, fere totam 

 longitudinem testse sequante ; margine anteriore et posteriore fere paral- 

 lelis. Long. -62, lat. -24, poll. 

 Hab. Beaufort Harbor, N. C. Wm. Stimpson, M. D. Coll. Smith- 

 sonian Institution. 



The above description is drawn up from a single valve obtained by Dr. 

 Stimpson in the harbor of Beaufort, N. C. It is so very different from the 

 other species of Rocellaria found on our Southern Coast and in the West 

 Indies, that I have not hesitated in regarding it as new. The great length of 

 the valve in proportion to its breadth, and the nearly parallel margins, dis- 

 tinguish it from R. o v a t a and R. h i a n s . In the latter, the beaks are 

 more nearly terminal. R. d u b i a of Europe, besides the above differences, 

 has a truncated posterior end, whilst this is regularly rounded ; and all the 

 above species are much more inflated, with a wider hiatus, than in R. Stimp- 

 sonii. 



The hinge exhibits small but well marked laminae. 



24. R. tenera, Deshayes, sp. 



Gastrochsena tenera, Deshayes, Zool. Proc. p. 327, 1854. 

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



Description. "R. testa elongato-angusta, tenui, pellucida, compressius- 

 cula, antice angusta, postice paulo latiore, subdilatata, antice apertissima, 

 hiatu totam altitudiuem jequante, lateraliter paulo sinuoso ; valvis antice 

 insequaliter tenue striatis, in medio distanter arcuato-subplicatis ; umbonibus 

 tumidulis, subterminalibus ; latere antico brevi, subhorizontali, in sutnra 

 cristato, et emarginato ; sinu pallii magno, profundo, triangulari, apice 

 acutissimo, basi lato." Deshayes. 



Hab. Philippines. Coll. Cuming. 



Subgenus Spengleria. 



25. R. Mytiloides,* Lamarck, sp. 



Gastrochsena Mytiloides, Lam. Anim. sans Vert. v. p. 447, 1818. 



" (Desh. ed.) Anim. sans Vert. vi. p. 49, 1835. 

 Hanley, Desc. Cat. p. 10, t. 9, f. 37, 1842. 

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

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

 (No name.) Rumphius, Amboinsche Rarit. t. 45, f. P, 1705. 



Description. " R. testa ovata; valvis area longitudinali pyramidata dis- 

 tinctis ; rugis transversis, fuscis." Lamarck. 1 inch long. 

 Hab. Isle of France. 



[Dec 



