Ill 



112. spissa, Quoy. 



113. spurca, Sow. 



114. squamosa, Linn. 



115. striata, Chemn. 



116. striatula, Costa. 



117. striatissima, Sow. 



118. strigosa, Lam. 



119. Stultzii, Dovan. 



120. Stuchburii, Gray. 



121. subimbricata, Sow. 



122. subrostrata, Reeve. 



123. subrostrata, Z«>». 



124. subrugosa, #o?p. 



125. tenuilamellata, id. 



126. thiara, Dillw. 



127. truncata, Zawz. 



128. undatella, Sow. 



129. undulosa, Zam. 



130. variabilis, Linn. 



131. varicosa, Sow. 



132. verrucosa, Xmra. 



133. Yatei, Gray. 



134. ziczac, Zm#. 



Figure. 



Venus Gnidia. PL 36. Eig. 195. Shell sculptured throughout with con- 

 centric lamellae of festooned erect scales. 



Genus 4. ARTEMIS, Poll 



Animal ; sub orbicular, its mantle freely open, the margins entire 

 or only partially serrated ; siphonal tubes long, united to their 

 extremities, margins of their orifices fimbriated ; foot semilunar. 

 (Forbes.) 



Shell ; orbicular, concentrically striated or ridged ; ridges some- 

 times laminated at the sides, especially at the posterior side, 

 area of the ligament generally excavated; lunule mostly well 

 defined ; hinge composed of three strong divergent teeth in one 

 valve and four in the other ; impression of the sinus of the 

 mantle lanceolately triangular. 



Artemis differs from the preceding genera of this family in the form of 

 the foot, in the siphons being united to their extremities, and in the mantle 

 having a triangularly lanceolate sinus, which is conspicuously impressed on 

 the shell. The peculiarities observable in the shell, in addition to that of 

 the pallial sinus, are its orbicular compressed form, its very uniform con- 

 centric sculpture and the general absence of colour and pattern, although 

 A. scalaris, ruf a, juvenilis, Chinensis, and a few others, including even our 

 British A. exoleta, are sometimes very expressively rayed with colour. The 

 shell has not the polished smoothness of Cythercea or the sculptural orna- 

 mentation of Venus, but the species are well distinguished from each other 

 in detail. 



As in the case of Tapes not more than a tenth of the species are found 

 in the Western Hemisphere; the remainder are natives of the Eastern 



