68 



PROCEEDINGS OF THE NATIONAL MUSEUM 



be a real one, or it may be a result of contraction or expansion of the 

 leg in preservative or of the possibility that regenerating and not fully 

 developed legs of P. minutus have been included among the material 

 measured. 



Table 1. — Synopsis of characters 



Planes cyaneus appears to be a somewhat larger form than P. 

 minutus. The smallest specimens of the latter examined measure 3.7 

 mm. in carapace length, and the largest 19 mm. Comparable measure- 

 ments for P. cyaneus are 5 and 25 mm. The mean carapace width is 

 usually about the same as the mean length in P. minutus, whereas it is 

 somewhat less in P. cyaneus (figs. 4, 5) ; this character is demonstrable 

 only in long series of specimens, however, and is of far less importance 

 than the length of the walking legs. 



