232 Notes on North Amerioan Crustacea. 



Pla§^nsia depressa. 



Plagusia depressa (Fabr.) Latr. ; M. Edw^ Hist. Nat. des Crust, ii. 93. 



Found on the west coast of Central America, by Capt. Dow. 

 It properly belongs to the Indo-Pacific fauna. 



Acantliopus planissimuis. 



Cancer planissimus Herbst. 



Plagusia clavimana Auct. ', Gibbes, Proc. Am. Assoc. 1850, p. 180. 



Acanthcpus planissimus Dana. 



Found at Key Biscayne, Fla., by Mr. Wurdemann, and at 

 Cape St. Lucas, by Mr. Xantus. 



Milne Edwards separates the "West Indian Acanthopus from 

 A. planissimus, under the name of A. gibbesii (Mel. Carcin. p. 

 146). They may be distinct, but we do not find the differences 

 mentioned by that author to be constant. 



We have but one specimen from Cape St. Lucas, in which 

 the antero-lateral margin is slightly concave anteriorly. It may 

 therefore belong to a distinct species from A. planissimus, but 

 we do not venture to decide upon this question until the arrival 

 of additional specimens which may enable us to observe whe- 

 ther the character be constant. 



Aratus pisoni. 



Sesarma pisoni M. Edw., Hist. Nat. des Crust, ii. V6 ; pi. xvii. f. 4, 6. 



Gibbes, Proc. Am. Assoc. 1850, p. 181. 

 Aratus pisoni M. Edw., Mel. Carcin. 153. 



Found at Key Biscayne, by Mr. Wurdemann, at the Tortu- 

 gas, by Capt. Woodbury, and at Charlotte Harbor, West Fla., 

 by Mr, E. B. Baker. The last-named gentleman informs me 

 that this species lives much on land, and climbs trees, even to 



