ENTOMOSTRACA OP THE SCOTTISH NATIONAL ANTAKCTIC EXPEDITION. 333 



Tribe CALIGOIDA. 



Genus Dysgamus, Steenstrup & Liitken, 1861. 

 Dysgamus atlanticus, Steenstrup & Liitken. (PI. XIII. fig. 13.) 



1861, Dysgamiis atlanticus, Steenstrup & Liitken, Bidrag til Kundskab om det aabne Hans Snijltelcreb 

 og Lernxer, p. 368, Tab. iv. fig. 8. 



Only the males of Dysgamus have apparently been observed hitherto, and it is 

 doubtful if the genus can be considered a valid one till females are obtained. 



The specimens on which the genus was founded were taken, probably while 



FIG. 1. Foot of first pair. 



FIG. 2. Foot of second pair. 



p. 5. 



KIG. 3. Foot of fourth pair. FIG. 4. Abdomen aiid fifth pair of feet. 



Dysgamus atlanticus, Steenstrup & Liitken. 



swimming freely at the surface, at several places in the North Atlantic, between lat. 8 

 and 28 N., and long. 21 and 36 W. 



This species has a close resemblance to Caligus in its general form and colour ; the 

 frontal plates are, however, without lunules or sucker-disks. The carapace is broadly 

 ovate and depressed, but the last two thoracic as well as the abdominal segments are 

 short and comparatively narrow. The first four pairs of thoracic legs are all two- 

 branched, and the branches two-jointed ; the first pair has the inner branch very small, 

 but in the other three pairs the branches are subequal ; there is, as in Caligus, a fifth pair, 

 very minute but quite distinct (see text-figures annexed). The eyes, though visible, are 

 not very conspicuous. The Scotia specimens were collected in the Atlantic at the 



(ROY. SOC. EDIN. TRANS., VOL. XLVIII., 579.) 



