OF MOLLUSKS FROM MAZATLAN. 270 



Genus Cycladei la. 



Tesfa hivalvis, tenuis, (pquilaterali!^, eeqincalvls, hnurJ himiit, nm^ 

 bonibus planatis. Ligamenfum tenuissimum, externum. Canlo 

 linea curvata, dent. lat. distatUibus, card, transversis, haud 

 radiuntibus. 



£6. CyCLADELLA PAPYRACEA, n. sp, 



C t. temdssima, subdiaphana, epidermide tenui induta, planata, 

 suborhiculari : concentnce fortiter lirata, liris rotundatis, ivtus 

 excavatis; tota mperjicie bneis granulosis radimitibus creber- 

 rimis minutisshne ccelnta; dent. card, i.-ii, transversis, mar- 

 gini dorsali subparaJlelis ; dent. lat. validis. 

 = " Tellina leburnea. Haul." (iragraents only), Maz. Cat. no 56. 

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

 " Lepton "), which he had found nestling ni a burrow in Spondylus. 

 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 the curve of the hinge-line, as 

 though unitnig the lateral teeth. The shell is too thin (being deeply 

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

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

 sionally, under KelliadfE, although in other respects its affinities 

 appear to be with (Edalia and CoopereUa. The hgament appears 

 little more than a prolongation of the ejjidermis. Beside the trans- 

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

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

 lunule in other shells. 



Long. -1, lat. -123, alt. -045. 



Hab. Mazatlan ; one perfect specimen frcm Harre CoUectioa 

 {Mils. Hani.) ; fragments, Liverpool Collection, 



706. ? MONTACUTA OBTUSA, n. Sp. 



?M, t. planata, valde incequiluterali, subrhomboidea ; subdia' 

 phana sen c/ialcedonica, haud punctata, Icevi ; marginibus pie- 

 rumque regulariter excurvatis, dorsali recto, lunbonibus haud 

 prominentibus ; cardine, vtraque in valva, dente uno cardinuli 

 et fossa ligamentali ; dent lat. altera valva elongatis, rectis, 

 altera vix conspicuis. 



Differs from ? M. dioncea in the elongation of the lateral teeti), 

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



Long. 047, lat. -06, alt. '01. 



Hab. Mazatlan ; two fresh specimens, Liverpool Collection, 



Tablet 2.j30 contains the larger specimen; the other is trana 

 parent. 



6y6. Pectun'Culus, sp. ind. 



Tablet 2.531 contains a minute valve, -033 across; outside wt»Ji* 

 ciuse, prominent concentric ridges, foliated by about twenty-ir»»ii 

 17 257 



