VENUS.— Plate I. 



oblique, thick, ventricose, cream-coloured, faintly 

 blotched and rayed with reddish-fawn, concentrically 

 densely ridged, ridges irregular, near the umboes 

 thin, then callous and flattened, latticed through- 

 out with radiating linear grooves, ridges ou the pos- 

 terior area serrately lamiiuited. 

 Desiiayes, Pro. Zool. Soc, 1853, p. 3. 



fenus Lisleri, var., Sowerbv. 



Ilai. 



It is somewliat doubtfid whether M. Deshayes is cor- 

 rect in separating this from F. Listeri. There is strong 

 evidence of its being a large callously-sculptured form 

 of that species. 



