88 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 5 



(1893) is based upon the examination of the tj^pe of P. octodentata 

 Rathbun (1906) (U.S.N.M. Cat. No. 32690) from Dominica, W.I., 

 and a cotype of P. quadridentata (Latreille) (1825) (U.S.N.M. 

 20280), type of the genus, type locality unknown, a gift of the Paris 

 Museum, as well as upon the type of Oediplax granulata Rathbun 

 (1893) (U.S.N.M. 17465) from Consag Rock in the Gulf of Cali- 

 fornia. The characters to which most importance is attached are the 

 shape of the merus of the third maxilliped and of the carpus of the 

 cheliped. In the new species the merus is distinctly produced as in 

 Pseudorhombila instead of quadrate as in Oediplax. With regard to the 

 shape of the carpus, our specimen is frankly intermediate between the 

 two genera, but still sufficiently angled to be called obliquely quadri- 

 lateral, instead of oval, as in Oediplax. 



Since the remaining characteristics upon which Miss Rathbun's genus 

 Oediplax was based, namely, the relative proportion of front to carapace 

 width and of anterolateral to posterolateral margins, are not borne out by 

 the second specimen of the type series, a small female, nor by other small 

 specimens in the Hancock collections, the necessity for the genus Oediplax 

 would seem debatable. Until more specimens, particularly males, are ob- 

 tainable, it will be impossible to settle this point satisfactorily. 



Genus GYRTOPLAX Rathbun 



Gyrtoplax panamensis Ziesenhenne, new species 



Plate 25, Figs. 1-4 



Type: Male, holotype, Cat. No. 388, Allan Hancock Foundation, 

 The University of Southern California, and female, allotype, from 

 Bahia Honda, District of Veraguas, Panama, 30-50 fathoms off North 

 Island; March 1, 1938; three males and one female, paratypes, same 

 locality and date; collected by Allan Hancock Expedition of 1938 at 

 Velero Station 863-38. One female, paratype, same locality, shore; 

 March 9, 1933 ; one male, paratype, same locality, 30-50 fathoms; March 

 28, 1939; collected by Allan Hancock Expeditions of 1933 and 1939 at 

 Velero stations 111-33 and 948-39, respectively. 



Measurements: Male holotype: length of carapace 5.4 mm., width 

 8.2 mm., width of front 2.9 mm., of fronto-orbit 5.7 mm., length of 

 major chela 5.6 mm., of major dactyl 3.2 mm. Female allotype: length 

 of carapace 5.1 mm., width 7.8 mm. 



Diagnosis: Carapace broadly hexagonal, length two thirds width. 

 Wrist coarsely granulate, a single, sharp spine at inner angle and a 



