OF MOLLVSKS FROM MAZATLAN. 270 



Genus Cycladei i a. 



Tesfa hh'dlvis, tenuis, (rqnilaferati.o, (cqi'ivcJvis, hnwl Man*, wwi- 

 bonifjus itldnatis. Ligainenfiiin teuumsim ,m, exfernum. Cardo 

 linea ciireata, dent. lat. distant iLus, ca d. trouscerais, haud 

 radiantibus. 



£6. Cycladella papyracea, n.sp, 



{.). t. tenuissimu, subdiftjihanrr, cpi. 'I'j-tnide fenvi indntn, pJanafa, 

 suborbiculari; conccnfnce f'ortiter Virata, Uns rotunilutis, intus 

 excavatis; iota supeijieie hneis (jranuluiiis radiantibus creber~ 

 rimis nnnutissime catlata; dent. card, i -ii. transversis, mar- 

 yini dursali subparat/elis ; dent, lat. vat dis. 

 = " Telliaa leburnea, Ilanl." (i'ragnients only), ^laz. Cat. no 06. 

 Mr. Iliinlev kindly sent for my inspection a perfect pair (as 

 *' Lepton "), which he haU found nestling ni a burrow in Spondt//us. 

 The hinge more resembles Ci/clas (Lam.) than any other known 

 genus. Its great peculiarity is, that the cardinal teeth, instead of 

 radiating from the umbo, fall in tlie curve of the hinge-line, as 

 though unitinjj the lateral teeth. Tiie shell is too thin (beiiiir dcenlv 

 uidented within by the concentric waves) to make out the pallial 

 line; but no trace of sinus is visible. It may therefore rank, provi- 

 sionally, under Kelliadcc, although in other resjiects its athnitiea 

 appear to be with (Edaliu and CoopereUa. The ligament appears 

 little more than a prolon!5ation of the ejudermis. Ueside the trans- 

 verse cardinal teeth, there is in each valve a curved line, slisihtlv 

 raised like the end of a finger-nail, which bounds what would be the 

 lunule in other shells. 



Long. -1, lat. -Vl.i, alt. -01.5. 



Hub. .Mazatlan ; one perfect specimen frcm Harre CoUectiou 

 (Jlilus. Hani.) ; fragments, Liverpool Collection, 



7OG. ? Montacuta OBTUSA, n.sp. 



fM. t. planata, valde intvquiluterali, subrhomboidea ; subdin- 

 phann sen chalcedunica, haud punctata, Uvvi ; mari/inibus ple- 

 rumqne rcyulariter e.ccurvatis, dorsali recto, umbonibus haud 

 proniincnfibus; cardine, vtraque n> vulva, dente uno cardinu/i 

 et fossa linamentuli ; dent lut. altera vulva elomjatis, reclta, 

 altera vix coiispicuis. 



Differs from ? ^1/. dioncea in the elongation of the lateral teetl), 

 and in the possession of a distinct cardinal tooth in each valve. 



Long. 047, lat. -Oti, alt. -01. 



Hub. iMazatlai) ; two frt-sh specimens, Liverpool Collection, 



Tablet 2.>oO contains the larger specimen ; the other is trans 

 parent. 



6y{i. Pectun'culus, sp. ind. 



Tablet 2."i;3l contains a ii<inute valvp, 033 across; outside w«.v 

 close, prominent concentric ridges, foliated by about tvveuty-fma 

 1 7 257 



