Notes on North American Crustacea. 51 



Actaea setig^er. 



Xantho 'setiger, Milne-Edwards ; Hist. Nat. des Crust., i. 390. 



Specimens from tlie Florida I^eys are in the Museum of the 

 Smithsonian Institution. 



Actaea erosa, nov. sp. 



Carapax convex anteriorly, flattened behind. The whole surface of 

 the body and feet above and below has a deeply eroded or vermiculated 

 appearance, being filled with small cavities, irregular in shape but nearly 

 uniform in size. The marmns of tlie cavities are fringed with short 

 pubescence. The carapax is areolated, but the divisions, with the 

 exception of the larger ones, are rendered indistinct by the character of 

 the surface. The anterior side of the carapax is gibbous over the front, 

 and somewhat contracted over the eyes. The two median lobes of the 

 front are conspicuously prominent, forming rounded teeth projecting 

 downward. Lobes of the antero-lateral margin indistinct. The surface 

 of the ischium-joint of the external maxillipeds is marked with one prin- 

 cipal eroded channel parallel to its inner margin, and extending the 

 whole length of the joint. There is a notch on the anterior margin of the 

 meros-joint of the same maxillipeds. Hands short and broad, with their 

 outer surface divided by furrows into longitudinal tuberculated ridges ; 

 the tubercles themselves are eroded and granulated ; fingers short, 

 grooved, and 4 — 5-toothed within. Ambulatory feet with hairy edges ; 

 dactyli pubescent. On the first three or four joints of the abdomen the 

 eroded cavities are transverse, and extend throughout the width of the 

 joint. The dimensions of the carapax in a male are : length, 0*73 ; 

 breadth, 1-01 inch. 



This species must be closely allied to Xantho vermiculatus^ 

 M.-Edw. 



It inhabits the coral-reefs of Florida. 



