I8l 



This species seems to have an equally wide distribution : it has been first recorded from 

 the Hawaiian Islands and afterwards from several stations near the Seychelles. The "Siboga" 

 record is intermediate between these widely distant localities. 



Dimensions in mm. : 



Length of carapace 4.85 



Breadth of carapace (just before posterior lateral teeth) 8.8 



Subfam. Goneplacinae. 



This group, which has bestowed its name upon the whole group, is readily characterized 

 by the elongate eye-stalks, and the narrow front. The greatest breadth of the carapace is lying 

 between the tips of the external orbital angles. In some cases the last segment of the sternum 

 is largely exposed, the base of the abdomen of the d' by far not reaching to the coxopodites 

 of the posterior legs, but the segment may be in other cases completely covered by the abdomen. 



To this subfamily only two genera are referred, Goneplax and Ommatocarcinus . 



Key to the genera : 

 Eye-stalks moderately elongate; front square-cut, not constricted . Goneplax Leach 

 Eye-stalks very long , thickening towards eye, front constricted 



between eye-peduncles Ommatocarcinus White. 



Goneplax Leach. 



1 8 14. Goneplax Leach. Edinburgh Encycl., v. 7, p. 430 {Goneplat on p. 393 is an evident 



typographical error) '). 



1815. Gonoplax Leach. Transact. Linn. Soc. London, v. 11, p. 323. 



1 8 16. Gonoplax Leach. Malacostraca Podophth. Brit., opposite pi. 13. 



This genus, on account of its elongate eye-stalks and the narrow front, bears a great 

 resemblance to MacrophtJialnitis^ with which it has been generally associated by earlier authors. 



The well known European species G. angulata (Fabricius) has long been the only 

 representative of the genus. Miers first recorded a species from the Indo-Malayan Archipelago. 

 Lately Miss Rathbun described two new species from the Indo-Pacific and Borradaile -) has 

 made known an interesting species {G. hirsutus) from the South Atlantic, near Rio de Janeiro. 

 The "Siboga" collection yielded two species. 



Key to the (Indo-Pacific) species^): 

 I. Lateral margins of carapace slightly converging backward, without 

 teeth, save the strong, spiniform external orbital angle ; anterior 

 margin of front somewhat concave. Meropodites of ambulatory 



i) Fide Rathbun, Pioc. Biol. Soc. Washington, v. 11, 1897, p. 167. 



2) British Antarctic ("Terra Nova") Exp., 1910, Zool., v. 3, n" 2, 1916, p. 100, textfig. :i. 



3) It must be mentioned here, that Alcock (Journ. As. Soc. Bengal, v. 69, prt 2, 1900, p. 317) records a small specimen of 

 Goneplax from the Persian Gulf, that resembles the European G. angulata^ but is distinguished by the want of the subterminal spine on 

 the anterior margin of the meropodites of the walking legs. 



33 



SIBOGA-EXPEDITIE XXXIX <:'. 24 



