ISOPODA. 51 



stout, with a flattened ventral edge armed with a couple of spines. The propodus 

 is stout, nearly as long as the dactylus, with a somewhat flattened edge vcntrally 

 and armed with a spine. The dactylus is rather stout at the base, tapering and 

 curved, with a spine or accessory claw about the middle of its length ventrally. 

 The remaining pereiopoda are much more slender, subequal in size, and comparatively 

 small ; the distal joints are cylindrical, and there is a stout curved seta on each 

 dactylus. 



Only a single specimen of this species was found among the dredge material 

 in February, 1902, before the ship was frozen in to Winter Quarters, inside the 

 20-fathom line. 



AUSTROFILIUS. 



Cephalosome three lobed, the median one forming a broad rostral plate, the 

 lateral ones flattened and bearing the small eyes. 



First antenna small. 



Second antenna, six-jointed peduncle, third joint with an external spine. 



Mesosome having its segments variable, but not distinctly divided into two 

 divisions. 



Metasome forms a single plate with small preterrninal biramous uropoda arising 

 ventrally. 



Pereiopoda all ambulatory, of moderate length. 



ADSTROFILIUS FURCATUS. 

 (Plate VIII. , fig. 2.) 



The cephalosome is not quite so broad as the first segment of the mesosome, 

 and over all it is about as long as the first two segments. The anterior part is 

 reduced to nearly half the diameter of the posterior, and tapering slightly it 

 terminates in two stout but widely separated spines. The antennae arise in the 

 rounded depression on either side of this rostrum, if such it may be called. The eyes 

 are small and dorso-lateral in position, borne on small rounded tubercles. 



The form of the mesosome is not easy to describe ; briefly, the six anterior 

 segments are separated from one another by conspicuous bands of dermis softer than 

 that which makes up the bulk of the segment. The first three progressively increase 

 in width, though only slightly, the remainder decrease in a similar way. 



The first segment is the longest, and is slightly curved forwards and of uniform 

 length throughout. Referring only to the harder parts the second is little more than 

 half the length in the mid-dorsal line, but increases laterally to be subequal in length ; 

 the third is intermediate in length, curved forwards laterally ; the fourth is straight. 

 The lateral margins of all these segments are more or less rounded and setose. The 

 fifth segment is the shortest, widening laterally, and not setose ; the sixth and seventh 



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