Notes on North American Crustacea. 69 



above punctate, with a slight but sharp transverse ridge, most prominent 

 in the male; surface behind the ridge oblique, nearly perpendicular. 

 There is much pubescence about the bases of the feet. In the chelipeds, 

 the fingers are longitudinal in both male and female, and gaping ; the 

 dactylus is armed with a tooth inside near the middle, and the immo- 

 vable finger with a tooth near the extremity. The ambulatory feet of 

 the third pair are very large and thick, but those of the second pair are 

 not much larger than the first. Color yellowish grey. Dimensions of 

 the carapax : — in a male, length, 0*22 ; breadth, 0*48 ; — in a female, 

 length, 0-32 ; breadth, 0-64 inch. 



This species lives with the lobworm {Arenicola cristata) in its 

 hole ill the sand, which is not lined by any tube. The young 

 occur in the early spring on slimy shores at low-water mark. 

 They were found by Lieut. Kurtz and myself near Fort Johnson, 

 harbor of Charleston, S. C. 



OXTSTOMATA. 

 lieiicosilia Jiirinii. 



Guaia Jurinii, De Saussure ; Rev. et Mag. Nat. Hist. 2rae Ser. v. 



pi. xiii. f. 4. 

 Leucosilia Jurinii, Bell. 



Found at Panama by the Rev. J. Rowell. 

 Randallia ornata. 



RandalUa ornata (Randall) ; Stimpson ; Crust, and Echin. Pacific 

 Coast of N. Am., p. 31, pi. xix. f. 3. 



This genus is more closely allied to Leucosilia than any other, 

 and is similar in the characters of the front. Tlie external 

 maxillipeds are not marked by a longitudinal ciliated ridge in 

 the female ; the exognath is widened at the base, and its obtuse 

 apex is overreached by the extremity of the endognath. The 

 pterygostomian canal over the exognath is tridentate at its 

 anterior margin as in Myra. 



