570 Monograph of the 



is in the adult. The pterygostomian region appears to be 

 pubescent over its whole surface in the young. In the 

 young there also appears to be no development of the in- 

 ternal angle of the lower margin of the orbit into a spine. 



The development of the spine on the carpus of the chel- 

 iped does not seem to be controlled by growth, but to be 

 wholly irregular. 



There are some anomalies not referable to growth, and 

 which we would naturally expect in examining many hun- 

 dred specimens. Sometimes we find specimens having 

 four spines on the anterior border of the meros of one chel- 

 iped, but in no specimen have I seen it on both cheli- 

 peds. In one specimen from Hayti there are on the carpus 

 of the left cheliped two spines, the second being at its 

 point of articulation with the manus ; another specimen 

 from the same locality has the same thing on the right 

 cheliped. I have seen a few specimens in which, al- 

 though it could not be said that there was a develop- 

 ment of two extra rudimentary teeth on the front, there 

 was yet a slight waviness of the edge, which is rather 

 a persistence of the embryological character than a varia- 

 tion. 



Color of living specimen : carapax, and the upper side 

 of the cheliped 3 and ambulatory feet, olive gi-een. The 

 inside of the chelipeds and sides of ambulatory feet, bright 

 blue. The dactyli of the chelipeds of the female are of a 

 bright red color and tipped with purple ; those of the male 

 are of a bright blue tipped with pur[)le. 



Range, from Nantucket to Mobile, and perhaps even 

 down to the Brazil coast. Its centre of distribution ap- 

 pears to be Chesapeake Bay. 



