84 



ASTARTE PLAXATA, SOW. PL 257, F. 2. 



"Spec. Char, transversely obvate gibbose, with small, obtuse, 

 concentric ridges ; edges crenulated ; lunule concave ; shell thick," 



" The ridges upon the surface are small, obtuse, close together, 

 and lost near the margin ; the edge is often very broad, flat, and 

 crossed by sulci, formed of extended crenulations, which are 

 visible even where the valves are close. The anterior side is 

 slightly truncated. 



This is a plain-looking shell in consequence of the smallness 

 of the ridges ; it is nearly two inches wide and above one inch- 

 and-a-half long when full grown.* 



This differs from the former in being decidedly gibbose. The 

 shell is thinner. 



Proportions Length, 24 lines ; breadth, 20 ; depth, 5. 



Bradford Abbas and Halfway-house, rare. 



ASTARTE MANSELLII (NOBIS) FIG. 3. 



Shell suborbicular, gibbose, upper margin nearly straight, 

 lines very fine, and numerous ; lunule very small. 



This shell is much like A. obliqua ; it is, however, decidedly 

 gibbose, and flatter. 



Proportions : Length, 22 lines ; breadth, 20 ; depth, 13. 



This shell is found rarely at Bradford Abbas, Halfway House, 

 and Clatcombe. 



ASTARTE EXPANSA (XOBIS). FIG. 4. 



Shell sub-triangular ; gibbose, upper margin slightly curved ; 

 very oblique ; lower margin semilunate ; lunule elongate, large ; 

 lines small, indistinct, and numerous. 



This shell has hitherto been confounded with A. excavata, but 

 it differs from it in being smooth, triangular, and oval, but 

 without an excavated lunule. 



Proportions : Length, 36 lines; breadth, 30; depth, 12. 

 * Sow, Min, Conch, vol. iii, page 103. 



