— 62 — 



clivem recurvata, sat crassula et opacula, rudenter 

 striata ac, prsecipue ad regioriem posticam, passim 

 subconcavo-malleata aut subgibbosa ; vix nitente, 

 subviolaceo-castanea (in junioribus), fusco-castanea 

 et ad umbones incolorata (in adultis) ; intus subvio- 

 lacea aut albescente ; — valvis antice aut postice 

 ssepe irregulari-contortis, uni-aut-bihiantibus (hian- 

 tise semper angustissimœ), vix convexis, fere com- 

 planatis (convexitas irregularis, maxima sat postico- 

 superior, e linea verticali 14, e natibus 19, e rostro 

 28, ab antico margine 33, ex angulo 12 et e basi ver- 

 ticalis 24 millim. remota ; supra regulariter arcuato- 

 gibbosa ; antice rotundata ; infra in medio subsi- 

 nuosa ; postice (regio postica obtusa quasi truncata, 

 sesquilongitudinem anterioris leviter superans et in- 

 ferne usque ad 23 millim. post verticalem leviter cres- 

 cens) in rostrum perobtusum, infra recurvatum atte- 

 nuata ; — umbonibus anticis, complanato-compressis 

 (nates peracutœ, bene margaritacese) ; sulco dorsali 

 convexiusculo, superne sulculo bene cavo eleganter 

 delimitato ; area exigua ; dente cardinali minute tu- 

 berculose* aut subedentulo ; lamella laterali postice 

 paulatim plane incrassatula ; ligamento posteriori 

 symphynoti ; lunella irregulari, subtriangulari aut 

 plus minusve semirotundata. 



MONCETIA ROCHEBRUNIANA 



Long. max. 45 ; ait. max. 27 ; ait. vertic. 25 ; 

 crass. max. 14; basis apico-rostralis 35; interval- 

 lum e natibus ad angulum 23, ex angulo ad ros- 



