JV^otes on North American Crustacea. 213 



the anterior margin of the meros-joint in the outer maxillipeds, 

 and bj the basal joint of the external antennne not being sol- 

 dered to the carapax. 



Daira americana was found at Cape St. Lucas, by Mr. 

 Xantus. The only other species known is an inhabitant of 

 the Indo-Pacific region. 



Piliiinniis xantiisii, nov. sp. 



Carapax narrow, moderately convex, anteriorly hairy, but posteriorly 

 short-pubescent like the abdomen. Gastric region and its principal 

 lobules well circumscribed. Two or three very short spines on the 

 hepatic and branchial region in a row parallel to the antero-lateral 

 margin. Surface elsewhere either smooth or sparsely roughened with 

 sharp grains. Front rather broad, deeply incised at the middle, but 

 without lateral incisions ; its margin armed with six small spines. 

 Superior margin of orbit straight, ciliated, but not armed with spines; 

 inferior margin with two or three spines toward the inner angle. Antero- 

 lateral margin armed with five spines, regularly placed and nearly 

 equidistant, but diminishing in size forward ; the anterior one at the 

 external angle of the orbit. Meros-joint of the external maxillipeds longer 

 than is usual in the genus, being nearly square, and less incised at the 

 internal angle. Chelipeds short and thick ; greater hand above and 

 externally hairy, and sparsely armed with spines ; surface between the 

 spines smooth and glabrous except toward the fingers, where it becomes 

 granulated, the spines disappearing or becoming tubercles ; lower margin 

 and inner side near the fingers granulated. Fingers tuberculated at- 

 base. Ambulatory feet not spinous but clothed above with very stiff 

 hairs. Color -reddish ; spines black ; fingers black. Length of carapax 

 in a male, 0.6; breadth, spines excluded, 0.68. 



It is the western analogue of P. aculeatus, but differs con- 

 siderably from that species in its narrower carapax, five-spined 

 antero-lateral margin, and in the want of spines on the feet. 



Found at Cape St. Lucas, abundantly, by Mr. Xantus. 



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