THE SPIDER CRABS OF AMERICA 223 



wider, with the eave wholly concave and the spines directed obliquely 

 outward. Rostral horns varying from 0.21 to 0.4 of the length of re- 

 mainder of carapace. Basal antennal article unarmed or with a very 

 low and inconspicuous tooth at anterior angle. Angles of buccal 

 cavity projecting, lobiform. vSubbranchial and pterygostomian re- 

 gions tuberculate. 



Chelipeds in male slightly enlarged, nearly as long as first ambu- 

 latory leg; merus somewhat angled, upper margin tuberculate proxi- 

 mally and with a distal spine. Carpus uneven; inner margin with a 

 thin lobe near the merus. Manus compressed, narrow, margins thin. 

 Dactylus about % the length of upper margin of manus, a large tooth 

 at base in the hiatus. Prehensile edges of both fingers denticulate. 

 Ambulatory legs of moderate length, with a tubercle at distal extrem- 

 ity of merus, or in the first pair a short spine. 



Extremely variable, variations independent of sex. 



Measurements. — Ovigerous female (11377), length of carapace on 

 median line 24.4, length of horn 7, width of carapace exclusive of 

 spines 18 mm. 



Range. — Off Georgia to St. Vincent, West Indies. Depth, 88 to 440 

 fathoms. 



Material examined. — See table, page 219. 



Genus LIBIDOCLAEA Milne Edwards and Lucas 



Libidoclaea Milne Edward.s and Lucas, d'Orbigny's Voy. I'Am^r. Merid., 

 vol. 6, pt. 1, Crust., 1843, p. 6; type, L. granaria Milne Edwards and Lucas. 



Carapace broadly pyriform, swollen above; branchial regions much 

 enlarged; gastric region prominent; genital region small, triangular, 

 its posterior part encroached upon by the branchial regions which at 

 this point are separated from each other only by a deep depression; 

 cardiac and intestinal regions very oblique. Surface rough with fine 

 granulations, sharp tubercles and spines. Rostrum long, extremity 

 bifid. Orbits deeply cut above and below; a strong preocular spine 

 above; eyes short, stout and retractile; basal article of antennae of 

 moderate width, with two spines or teeth on outer margin. Buccal 

 cavity closed by outer maxillipeds. Anterior portion of sternal 

 plastron very oblique; abdominal segments distinct in both sexes. 

 Chelipeds elongate; not surpassing the next pair of legs; fingers long, 

 slender, and denticulate on inner border. Ambulatory Ipgs slender, 

 diminishing successively in length; dactyli long, slender, and slightly 

 curved. 



Southern part of South America. 



KEY TO THE SPECIES OF THE C.ENUS LIBIDOCLAEA 



A'. Rostrum less than one-third as long as remainder of carapace and bifurcate 

 for less than half its length granaria, p. 224- 



A^. Rostrum more than one-third as long as remainder of carapace (intestinal 

 spine excluded) and bifurcate for half its length smithii, p. 226. 



