— 63 — 



trum 16, e rostro ad verticalem 26 et e basi verti- 

 calis ad angulum 27 ; regio antica 1 6 , postica 

 30 millim. 



Concha complanata, in directionem declivem sub- 

 pathuliformi-oblonga, inferne post verticalem levi- 

 ter sinuosa, postice late obtusa, superne notabiliter 

 gibbo«o-arcuata et inferne leviter subrecurvata , 

 opaca, non nitente, concentrice striata (striœ crebraî 

 ac sat productse), uniformiter rubello-cornea, postice 

 limo fore semper inquinata ; intus albescente, parum 

 margaritacea ; — valvis antice sat aperte hiantibus, 

 parum convexis, postice complanatis (convexitas me- 

 diocris, maxima superior, e linea verticali 14, e na- 

 tibus et ex angulo œque 12, e rostro 23, ab antico 

 margine 25 et e basi verticalis 18 1/2 millim. re- 

 mota) ; — supra regulariter arcuata et prœcipue e 

 natibiis usque ad rostrum gibboso-descendente ; an- 

 tice rotundata ; infra decliviter rectiuscula ac post 

 verticalem leviter subsinuosa ; postice (regio postica 

 duplicem anterioris non attingens et inferne usque ad 

 15 millim. post verticalem leviter crescens) in ros- 

 trum late obtusum, infraque adspicientem , atte- 

 nuata ; — umbonibusanticis, compressis (nates decor- 

 ticatœ) ; sulco dorsali in directionem arcuatam con- 

 vexo ; area nulla ; dente cardinali elongato, obsolète 

 incrassato ; lamella laterali plane lamelliformi ac 

 incrassatulà ; ligamento posteriori symphynoti ; lu- 

 nella minute triangulari. 



MONCETIA JOUBERTI 



Long. max. 63; ait. max. 31 1/2; ait, vertic. 30; 

 crass. max. 16; basis apico-rostralis 52; interval- 



