DR. P. P. CARPENTER ON THE SHELLS OF PANAMA. 25 



have hollow umbos. One long shell, first marked e, but altered to d, 

 is the adult form ; several of the younger shells are doubtful. 



384. Ostrea, sp. ind. e. = Ostrea, M. 215. Being a good species, 

 I propose the name of 0. amara. The Professor's " small var." is 

 not plicated, and appears to belong to O. conchaphila, M. 214. 

 [N.B. Additional specimens confirm me in the belief that O. pal- 

 mula, M. 214 b, is a distinct species.] 



385. Spondylus lamarckii, C. B. Ad. = S. calcifer, M. 208. 



386. Spondylus, sp. ind. a = Plicatula penicillata, M. 210. 



387. Pecten inca=P. ventricosus, Sby., as in errata. 



388. Pecten tumbezensis=P. aspersus, Sby., Hani. (? Lam.). 



389. Lima angulata. Shells inflated, not gaping. 



390. Lima pacifica (=L. arcuata, Sby., Hani.). Young shells, 

 species uncertain. 



391. Avicula 1maryaritifera = Maryaritiphora fimbriata, Dkr., 

 M. 204 = M. mazatlanica, Hanl. = Jf. barbata, Rve. 



392. Avicula sterna, M. 203. A. libella, Rve., appears to me 

 the young of this specie*. 



393. Perna, sp. ind. a = Isoynomon chemnitziana, M. 205. 



394. Perna, sp. ind. b I. chemnitziana, var. Rather more 

 finely grown, and with less colour, but certainly the same species. 

 The Professor's Jamaica specimens are labelled " bicolor, Ad." 



395. Pinna maura, M. 200. 



396. P'rtna tuberculosa. Three of the specimens appear to me 

 = P. maura, jun. The other may be the same, but is worn nearly 

 smooth. 



397. Mytilus, sp. ind. a. Resembles the young of Modiola bra- 

 siliensis, but with a few hinge-teeth, as in M. edulis. 



398. Lithodomus, sp. ind. a. Most of these specimens are of 

 Lithophagus aristatus, M. 176 ; one (perhaps two) are L. attenua- 

 tus, M. 173 (which is found from Lower California to Chili) ; and 

 one appears to be L. plumula, M. 1 75 ; but they are too young to 

 decide with confidence. 



399. Modiola ? semifusca. These specimens all belong to the M. 

 brasiliensis, M. 1/1, but are much more like the ordinary Brazilian 

 specimens than are those from Mazatlan. As compared with the 

 latter, the Panama shells are more rounded, with stronger posterior 

 grooving, and with the angular ridge less marked. A similar shell, 

 undoubtedly from New Zealand, is considered by Mr. Cuming con- 

 specific. 



400-404. Modiola, sp. ind. a, b, c, d, e. I could find no a or e 

 in the collection; but there were two trays marked/. Tray b M. 

 capax, M. 170. c contains several specimens of Mytilus multiformis, 

 M. 168, strongly ribbed variety, perhaps intended for b, no. 401. 



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