THE SPIDEK CRABS OF AMERICA 529 



PARTHENOPE (PSEUDOLAMBRUS) EXCAVATA (Stimpson) 



Plate 189 



Lambrus excavatus Stimpson, Ann. Lye. Nat. Hist. New York, vol. 10 

 1871, p. 98 [125] (type-locality, Manzanillo, Mexico; type not extant). — 

 A. Milne Edwards, Crust. R6g. Mex., 1878, p. 154. 



Diagnosis. — Antero-lateral margins angled, the outer part parallel 

 with axis of body. Five deep depressions on anterior half of body. 

 Chelipeds deeply concave above, upper margins of palm 4- and 6- 

 toothed. 



Description. — Carapace irregularly hexagonal, broader than long; 

 antero-lateral margin concave, forming an angle with outer lateral 

 margin which is nearly straight and parallel with axis of body and 

 terminates posteriorly in a strongly projecting angle; postero-lateral 

 margins slightly concave, forming a very obtuse angle with each 

 other on account of the little projection of the intestinal region; 

 periphery armed with teeth which are short, triangular, and regularly 

 approximated on the antero-lateral and outer lateral margins but 

 are longer, more spiniform and irregularly arranged on the postero- 

 lateral margins. On the upper surface, besides the usual depression 

 between cardiac and branchial regions there are four deep excava- 

 tions in front of the latter region, two separating it from the hepatic 

 and two from the gastric region; also a deep concavity on the frontal 

 region, which is continued posteriorly for a short distance on the 

 gastric region. Rostrum large, regularly triangular, deflcxed to a 

 right angle with general level of gastric region; margin unarmed or 

 only obscurely toothed. Surface of protuberant parts of carapace 

 covered with low, granulated tubercles. A row of three fiat, triangu- 

 lar spines on ventral surface behind cheliped. 



Chelipeds much shorter and stouter than in typical Parthenope, 

 deeply concave above, concavity smooth or nearly so, and defined 

 by prominent marginal crests, which, except on carpus, arc strongly 

 toothed; merus particularly short, anterior crest armed with three or 

 four teeth, superior crest with only two large teeth, the outer much 

 the largest; crest of superior margin of hand armed with six unequal 

 approximated, triangular teeth, that of outer margin with two conical 

 distant teeth besides the knob at each extremity, lower surface 

 ornamented with four or five rows of granulated tubercles, those of 

 middle row largest and most conspicuous ; inner margin serrated with 

 granulated teeth. Feet much compressed, crested above, margins 

 dentate, dactyli furred. Each segment of female abdomen armed 

 with short, setose, granulated tubercles, there being on segments 

 two to six, a larger ridge-like tubercle in middle and four or five small 

 ones on each side. (After Stimpson.) 



