THE CUMACEA OF THE SIBOGA EXPEDITION 



BY 



W. T. CALMAN, D.Sc. 



British Museum (Natural History). 



With 2 plates and 4 text-figures. 



The collection of Cumacea obtained by the ".Siboga" Expedition, although not very 

 large, is of considerable interest and importance. Eleven species, all of which except one are 

 regarded as new, are discussed below, while some eight additional species of which the material 

 is considered insufficient for exact determination, are referred to under their respective genera. 

 Several of the species are of exceptional size and of striking characters. One is referred to a new 

 genus (Pseudodiastylis) which is in some respects intermediate between the families Diastylida: 

 and Lampropid(T\ another (Heferociniia Weberi), one of the largest Cumaceans hitherto described, 

 is only provisionally referred to the genus Hctcrocitiua and ma)- ultimately require to be removed 

 to a new genus; while a third (Cyclaspis Sibogcs) helps to diminish the narrow space separating 

 the genera Cyclaspis and Bodotria. The discovery of a second species of Paradiastylis has 

 revealed the existence of a somewhat remarkable difference between the sexes of this eenus. 



Our knowledge of Cumacea from extra-European seas is still so exceedingly fragmentary 

 that it seems unnecessary to comment on the geographical relations of the species here described. 

 No Cumacea have hitherto been recorded from the area traversed by the "Siboga". Two species, 

 however, were obtained by the "Challenger"" at Samboangan, Philippine Islands, and one of them, 

 Natinastacus sii/uiiii, has been identified in the present collection. The "Challenger" also dredged 

 two species in Flinders Passage, between Australia and New Guinea, and one of these, Cyclaspis 

 exsculpta Sars, is closely allied to the form described below under the name C. perscttlpta. 



SIBOGA-EXPEDITIE XXXVI. 



