DECAPOD CRUSTACEA FROM MADAGASCAR. 



Measurements of Potamon madagascariense. 



917 



Series A. — These specimens are all, without much doubt, 

 refei-able to the typical form of F. madagascariense as described 

 and figured by A. Milne-Edwards and by Miss Rathbun. The 

 characters in which they diii'er among themselves are relatively 

 unimportant, with two exceptions, viz. : — (1) the distance between 

 the epigastric and the postorbital crests, which, in the largest 



