444 MR. H. ADAMS ON SHELLS FROM EASTERN PERU. [Nov. 22, 



49. Anodonta (Lamproscapha) ensiformis, Spix. 



50. Monocondyl^ea (Plagiodon) ? isocardioides, Lea. 



Fam. Mycetopid^e. 



51. Mycetopus soleniformis, D'Orb. 



Fam. Mutelid^e. 



52. Castalia cordata, Humph. 



53. Leila gigantea, Lea. 



54. Leila blainvilliana, Lea. 



55. Triquetra corrugata, Lam. 



Several examples of this very fine species in most perfect condition. 



56. Triquetra obliqua, Schum. 



Fam. ^Etheriid^e. 

 Bartlettia, gen. nov. 



Testa libera, cequivalvis, incequilateralis , clausa ; superficies valva- 

 rum rugosa velfoliata, epidermide olivaceo-viridi induta. Cardo 

 edentulus ; ligamentum breve, crassum, pnecipue internum, laminis 

 validis, curvatis, prominentibus suffultum ; impressiones muscu- 

 lares duce, anterior elongata, angusta, posterior ovalis, ampla ; 

 linea pallialis simplex. Intus margaritacea. 



57. Bartlettia stefanensis, Moric. (PL XXXVIII. fig. 7.) 



B. testa falcata, solidiuscula, anlice irregulariter producta, angusta, 

 torta, postice rotundata, margine ventrali valde sinuato, anteriore 

 lobato ; superficie valvar am antice irregulariter rugose plicata, 

 postice angulata, concentrice crasse striata. 



Long. 75, lat. maj. 35, minor 20, alt. 27 mill. 



Etheria stefanensis, Moric. Journ. Conch, v. (1856) p. 178. 



This singular shell was first met with by M. Porte in the Amazon, 

 near its embouchure, and was described by M. Moricand as a species 

 of JEtheria. M. Moricand supposed it to be adherent like the other 

 species of that genus, and probably by a small portion of the surface 

 of one valve near the beak, which was broken away in both of the 

 specimens received by him. There are no traces, however, of any 

 such adherence in the more perfect examples collected by Mr. Bart- 

 lett ; and the shell, not possessing this peculiarity, and differing also 

 materially in other respects from JEtheria, forms, in my opinion, the 

 type of a distinct genus. The other differences to which I allude 

 are : — the ligament being marginal like that of Anodonta, and not 

 sunk in a groove of the area of one valve ; the internal surface being 

 without the blisters present in both the species of the African genus ; 



