442 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 21 



Parthenope (Platylambrus) depressiuscula (Stimpson) 

 Plate Z,, Figs. 4, 4a ; Plate 49, Fig. 1 



Lambrus depressiusculus Stimpson, 1871a, p. 101. A. Milne Edwards, 



1878, p. 155. 

 Parthenope (Platylambrus) depressiuscula, Rathbun, 1925, p. 524, pi. 

 188. Garth, 1948, p. 31. 



Type: Male holotype, length 21.6 mm, width including spines 29.2 

 mm, length of manus 29.2 mm ; not extant. 



Type locality: Manzanillo, Mexico; John Xantus, collector. 



Localities subsequently reported, with collectors: Panama: Henry A. 

 Ward, purchased (Rathbun) ; Isla Rayonetta, Perlas Islands, 8-9 m, 

 Askoy (Garth). Colombia: Malaga Bay, 4-9 m, Askoy (Garth). 



Atlantic analogue: Parthenope (Platylambrus) guerini (Brito 

 Capello). 



Diagnosis: Carapace depressed, constricted behind orbits, branchial 

 regions broadly expanded. Tubercles small, sharp, scattered. Largest of 

 anterolateral spines at lateral angle ; a larger spine at end of branchial 

 ridge. Rostrum small, trilobate, horizontal. Fingers bent at right angles 

 to hand. Male first pleopod long, slender, tapering, tubular, opening 

 terminal ; densely and finely pubescent at base, a line of stouter setae 

 proximally on lip of groove, a line of finer setae extending the length of 

 groove as well as other lines marginally. Male second pleopod less than 

 half as long as first, sinuous, basally broadened, terminally pointed, a 

 subterminal denticle. 



Description: Body depressed, though much less so than in P. (P.) 

 serrata. Carapace two-fifths broader than long, regions moderately prom- 

 inent, the cardiac region most so; surface covered with scattered, berried 

 tubercles, irregular in size. Branchial region broadly expanded. Lateral 

 margin armed with 14 or 15 spiniform, granulated teeth; two of these 

 in front of the cervical suture, and five on the postlateral margin ; of the 

 latter, the second longest of all, recurved, and at the end of the branchial 

 ridge. The spine at the lateral angle, at the widest part of the carapace, 

 a little longer than those on either side of it. Intestinal region broad, 

 projecting but little beyond line of posterolateral angles ; bordered by 

 seven tubercles, the end ones the largest and the two on either side of 

 the median one next in size. Frontal region concave ; rostrum small, tri- 

 iangular or trilobate, horizontal. Subhepatic and pterygostomian regions 

 moderately guttered. 



Upper surface of merus of cheliped armed with a row of about five 

 unequal tubercles ; margins of merus and manus armed with numerous 



