DR. P. P. CARPENTEH on the shells of PANAMA. 29 



472. Tellina sincera-=Striyina 8. 



473. Tellina vicina=^Heterodonax vicinus. The shells are la- 

 belled T. versicolor hy the Professor. They are larger than the ge- 

 neral run of West Indian specimens ; but the form is probably a 

 local variety of the old Heterodonax biinaaulalus. 



474. Tellina, sp. ind. a. The doubt concerning "concave" and 

 "convex" probably arises from an error in description. 



47.5. Tellina, sp. ind. b. Looks exactly like the young of No. 474, 

 but with lateral teeth. 



476. Tellina, sp. inu. c. Dead valves of T. felix. No. 465, 



477. Petricola cognata. More characteristic specimens from the 

 same coast are affiliated by Mr. Cuming to P. pholadlformis, from 

 which this would probably not have been separated had it appeared 

 on the Atlantic coast. 



478. Saxicai'a 1 tenuis. The Panama shell is more like Petricola 

 than Saxicava, having two teeth in each valve, one of which is bifid. 

 Sowerby's species is called by Messrs. H. & A. Adams " Saxicava 

 tenuis'"' (ii. p. 349) and " Petricola tenuis" (ii. p. 441). Shell with 

 very fine radiating striae, crossed by irregular striae of growth. 



479. Cumingia coarctata=C. lamellosa, var., M. 42. 



480. Cumingia trigonularis, M. 43. • . 



481. Cumingia, sp. ind. a=C. trigonularis, No. 480. 



482. Cumingia, sp. ind. b=C. var. coarctata. No. 479. 



483. Cumingia, sp. ind. c=M. 4.5. This appears a distinct spe- 

 cies, and may be quoted as C. adamsii, in remembrance of the labours 

 of Messrs. H., A. and C. B. Adams. 



484. Cumingia, sp. ind. c?=Maz. Cat. tablet 107, p. 31; well 

 rounded, with close striae. Probably distinct. 



485. Amphidesma bicolor=Semele Ivenusta, M. 41 (non A. Ad.). 

 The "species" in this genus are often separated by very variable 

 characters. 



486. Amphidesma lellipticum= Semele e. 



487. Amphidesma proximum. The type is not quite so elliptical 

 as the last species ; but as this is a very variable character (i'. Maz. 

 Cat. p. 2*1), I should regard it as the same. It is not the Semele 

 proxima, M. 40 (=^S.^avescens, v. Maz. Cat. p. 548). 



488. Amphidesma pulchrum= Semele p. 



489. Amphidesma striosum = Semele s. I should describe the 

 shell as smooth, with very fine diagonal striae crossing the lines of 

 growth. It has the general aspect of S. pulchra. The teeth in one 

 valve are long and sharp. 



490. Amphidesma tortuos%im=^ Semele t. Teeth short and faint. 



491. Amphidesma ventricosum-^ Semele V. The " zones " are rery 



203 



