PART 1 GARTH : PACIFIC OXYRHYNCHA 447 



few setae on lip of groove, a row of subterminal setae. Male second 

 pleopod three-fourths as long as first, sinuous, tip blunt, a subterminal 

 cluster of denticles. 



Description: Carapace irregularly hexagonal, and one-sixth broader 

 than long. Anterolateral margin concave, forming an angle with the outer 

 lateral margin, this margin nearly straight and parallel with the axis of 

 the body, and terminating posteriorly in a strongly projecting angle. 

 Posterolateral margins slightly concave, and forming a very obtuse angle 

 with each other because of the slight projection of the intestinal region. 

 Periphery armed with teeth, short, triangular, and regularly approxi- 

 mated on the anterolateral and outer lateral margins, but longer, more 

 spiniform, and irregularly arranged on the posterolateral margins. On 

 the upper surface, besides the usual depression between the cardiac and 

 branchial regions, four deep excavations in front of the latter region: 

 two separating it from the hepatic, and two, somewhat larger, from the 

 gastric region. A deep concavity on the frontal region, continued poste- 

 riorly for a short distance on the gastric region. Rostrum large, regularly 

 triangular, and deflexed to a right angle with the general level of the 

 gastric region ; margin unarmed, or only obscurely toothed. Surface of the 

 protuberant parts of the carapace covered with low, granulated tubercles. 



Chelipeds much shorter and stouter than in typical [Parthenope], 

 and deeply concave above, the concavity being smooth or nearly so, and 

 defined by prominent marginal crests, strongly toothed except on the 

 carpus. Merus of the cheliped particularly short ; its anterior crest armed 

 with three or four teeth, its superior one with only two large teeth, the 

 outer one much the largest. In the hand, the crest of the superior margin 

 armed with six unequal, approximated, triangular teeth ; and that of the 

 outer margin with two conical distant teeth, besides the knob at each 

 extremity. Lower surface of the hand ornamented with four or five rows 

 of granulated tubercles, those of the middle row being largest and most 

 conspicuous ; inner margin serrated with granulated teeth. Ambulatory 

 [legs] much compressed, and crested above. 



In the female abdomen each segment armed with short setose tuber- 

 cles, there being a larger ridge-like one ... in the middle, and four or 

 five small ones on each side. (Stimpson, modified) 



In the male abdomen the larger ridge-like tubercles restricted to seg- 

 ments 2 through 6, the smaller lateral ones to segments 2 through 4 

 only. 



Material examined: 6 specimens from 5 stations. (See Table 97) 

 From Angel de la Guarda Island, Gulf of California, Mexico, to 

 Taboga Island, Panama. 



