NO. 3 GARTH : SOME NEW SPECIES OF BRACHYURAN CRABS 79 



shows the epistomal and antennular area much less sunken and the flagel- 

 lum of the antenna lodged in the orbital hiatus in the usual manner. The 

 oblique anterior border of the merus of the outer maxilliped, the quadri- 

 fid front, well separated from the dentiform orbital angles, the inferior 

 position of the basal antennal article, the disproportionate size of the 

 claws, and the seven free male abdominal segments constitute the argu- 

 ment for placing the proposed new species in the genus Platyxanthus. 



This handsome and readily distinguished species is named in honor 

 of Vasco Nunez de Balboa, who near its Panamanian type locality first 

 set eyes on the Pacific Ocean, thereby opening it to conquest by science as 

 well as by Spain. 



Genus HEXAPANOPEUS Rathbun 



Hexapanopeus costaricensis, new species 

 Plate 21, Figs. 1-4 



Type: Male, holotype, Cat. No. 78779, U.S. National Museum, and 

 female allotype, from Port Parker, Costa Rica, 5 fathoms, sand and 

 shell; February 9, 1935; collected by Allan Hancock Expedition of 

 1935 at Velero Station 468-35. Six specimens, paratypes, from Puerto 

 Culebra, Costa Rica, 3-10 fathoms, February 24, 1934; 22 specimens, 

 paratypes, same locality, 10 fathoms, February 25, 1934; two specimens, 

 paratypes, from coral, same locality and date ; collected by Allan Hancock 

 Expedition of 1934 at Velero stations 254-34, 257-34, and 258-34, re- 

 spectively. 



Measurements: Male holotype: length of carapace 5.2 mm., width 

 6.9 mm., of front 2.6 mm., of fronto-orbit 5.0 mm., length of major 

 chela 5.2 mm., of dactyl 3.4 mm., height of claw 2.8 mm. Female allo- 

 type: length 4.0 mm., width 5.6 mm. 



Diagnosis: Front slightly oblique, almost truncate, without lateral 

 lobes. Second lateral tooth fused with first, their combined width equal 

 to that of the third. Fourth and fifth teeth acute, thickened, and up- 

 turned. Chelae with prominent superior sulci. Carpus of walking legs 

 deeply furrowed. Tip of male abdomen broad, rounded. 



Description: Carapace hexagonal, regions well defined both anteri- 

 orly and posteriorly, granules becoming more distinct toward lateral and 

 frontal margins and larger on the transverse gastric and branchial ridges. 



