EXPLANATION OF PLATE XXXI. 



FIGURE 233. Crenella glaudula, (p. 695.) 

 234._Mytilu8 edulis, (p. 692.) 

 235. Modiolaria corrugate, (p. 694.) 

 236. Modiolaria nigra, (p. 694.) 

 237. Modiola modiolus, (p. 693.) 

 238. Modiola plicatula, (p. 693.) 



(All the fissures are 



of natural size, and from Binney s Gould, drawn by E. S. Morse.) 



