Dr. P. P. Carpenter on new Forms of Mollusks. 311 



XXXII. — Diagnoses of new Forms of Mollusks collected at Cape 

 St. Lucas by Mr. J. Xantus. By Philip P. Carpenter, 

 B.A., Ph.D. 

 The specimens here described belong to the Museum of the 

 Smithsonian Institution, Washington, D. C. The first available 

 duplicates will be found in the British Museum or in the 

 Cumingian Collection. An account of the labours of Mr. Xantus 

 will appear in the forthcoming volume of British Association 

 Reports ; and detailed notes on the species may be consulted in 

 the American scientific periodicals for the current year. 



Genus Asthength^rus*. 



Testa extus "TkracicB" similis : intus cardine edentulo, baud 

 spathulato ; cartilagine infra umbones sita. 



1. Asthenothcerus villosior. 

 J. testa insequivalvi, insequilaterali, umbonibus ad trientem lon- 

 gitudinis sitis ; tenuissima, alba, (sub lente) omnino minutissime 

 et creberrime pustulosa ; rugis incrementi obtusissimis, irregulari- 

 bus, maxime t. juniore, ornata ; epidermide tenui, pallide olivacea 

 induta ; parte postica truncata, parum hiante ; antica valde rotun- 

 data; marginibus dorsalibus et ventrali parum excurvatis; um- 

 bonibus angustissimis ; regionibus lunulari et nymphali subcari- 

 natis : intus, margine cardinali utriusque valvse acuto ; ligamento 

 inconspicuo ; cartilagine subspongiosa, satis elongata, postice de- 

 flecta; fovea baud indentata; cicatricibus adductorum parvis, 

 subrotundatis ; sinu pallii majore, ovali, ad dimidium interspatU 

 porrecto. Long. -38, lat. -26, alt. -14 polLf 



2. Solemya volvulus. 



S. testa minore, tenuissima, diapbana, vix testacea, cornea, pallidiore, 

 lineis tenuibus, distantibus, fuscis, radiatim ornata ; postice tenui- 

 ter radiatim striata ; tumente, satis elongata, marginibus antico et 

 postico regulariter excurvatis ; umbonibus vix conspicuis ; lineis 

 anticis divaricantibus, extus parentibus, intus lacunam cartila- 

 gineam definientibus ; cardine edentulo ; ligamento postice elon- 

 gate, antice curto, latiore, bifurcate ; cicatricibus adductorum 

 subrotundatis. Long. 'SS, lat. '25, alt. '14 poll. 



3. Tellina {Peronceoderma) ochracea. 



T. testa majore, parum inaequilaterali, tenui, satis planata ; cameo- 

 ocbracea, intus intensiore ; Isevi, nitida, marginem versus striis 

 incrementi ; postice vix radiatim striatula ; ventraliter antice 

 valde excurvata, postice vix angulata ; marginibus dorsalibus ob- 



* 'Ao-^6i/^f, weak ; Oaipos, binge. 



f The measures of length are taken from the anterior to the posterior 

 margins. 



