MONOGRAPH OF THE GENUS 



VENUS. 



Fam. Venerida?. 



Char. Gen. Testa aequivalvis, inaequilateralis, plerumque ovalis 

 seu orbicularis ; impressionibus muscularibus duabus subrcnifor- 

 mibus ; pallii impressione plerumque postice plus minus sinuata ; 

 ligamento extcrno ; lunula impress;! ; cardine dentibus duobus et 

 tribus cardinalibus. 



In tbe Cyfherma there is a lateral tooth near, and anterior to, 

 the diverging cardinal teeth ; this is wanting in most of the true 

 Veneres, and although in the orbicular group, which has been 

 separated under the generic name " Dosina," a slight indication 

 exists of a similar tooth, it is so rudimentary as to be almost 

 imperceptible. The genus includes some very different-looking 

 groups, which yet pass so gradually into each other as to render 

 a division into distinct sections impracticable. All the species 

 however, from V. puerpera to V. gallina, have a crenulated inner 

 margin, and the few from V. striata to V. aquilatera have it 

 smooth. 



1. Venus puerpera (pi. clii. f. 1, ?,), Linn. Mantissa, 

 p. 545. Venus reticulata. 



V. testa ponderosa, ventricosa, subrotundata, sulcis planulatis 

 radiantibus et costellis concentricis antice crassiusculis submonili- 

 feris erectis postice sublaminatis decussata; pallide fulva, fusco 

 variegata et purpureo (postice praecipue) obscure radiata, intus 

 postice purpurea; latere postico magno, subtruncato; marginc 

 dorsali elevato, arcuato, longitudinaliter plicato ; latere antico 

 brevissimo, umbonibus depressis; lunula magna, linea impressa 

 circumscripta ; margine ventrali intus crenulato. 



Thick, ventricose, rather rounded, with flattened radiating rib- 

 lets, crossed by rather thick concentric ribs, which are inclined to 

 be laminar at the hinder part of the shell, and beaded or scalloped 



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