EXPLANATION OF PLATE XXXIL 



Figure 239.— Auomia aculeata, (p. G97 ;) lower side, natural size. 

 240.— The same, upper side. 



240a. — The same, portions of the upper side magnified. 

 241. — Anomia glabra, (p. 606 ;) proiile view, natural size. 

 242.— The same, (p. 696 ;) lower side 

 242a. — The same, (p. 696 ;) young, natural size. 

 243.— Pecten irradians, (p. 695;) natural size. 

 244.— Siliqua costata, (p. 675;) natural size. 

 245.— Ensatella Americana, (p. 674 ;) natural size. 



(The figures are from Binnej-'s Gould, drawn by E. S. Morse.) 



