ISOPODA. 69 



papilliform teeth occur on the inner margin. The palp is five-jointed ; four joints are 

 short and broad ; the terminal one is also short, and, though much more slender, it 

 is more correctly described as a stump. The three central joints are each provided on 

 the inner border with two or three long setse, and the third of the entire series is 

 the largest. 



The pereiopoda, except the first, are uniform in structure. The first is short and 

 comparatively stout ; the basis is long ; the ischium little more than one-third the 

 length ; the nierus is quite short and expanded distally ; the carpus is a little longer, 

 much expanded veutrally to form a round " cutting " edge which carries two stout 

 spines. The propodus is a little longer still and similarly expanded veutrally, but not 

 quite throughout the entire length of the joint; the dactylus is about as long, slender, 

 and bears a slender claw distinct from the joint and a much smaller though distinct 

 accessory. A few setse are scattered throughout the appendage. 



The other appendages are slender, but not so long as the body. The basis 

 is little longer than the ischium ; the merus is short and swollen dorsally. 

 The other joints are comparatively long and become increasingly slender ; the 

 propodus is a little longer than the carpus, and each of these have two spinous 

 setse ventrally. The dactylus is slender, slightly curved, rather more than half as 

 long as the propodus. 



The pleopoda are protected by a sort of hood formed by the urosome, and the 

 first pair forms a shield to the rest. The ovigerous female is much broader than 

 the male. 



Four specimens were taken in Winter Quarters inside the 20-fathom line in 

 February, 1902. 



NOTOPAIS. 



Cephalosome broad and short, excavated in front and without eyes. 



Mesosome with the three posterior segments recurved, tapering and separated 

 from the four anterior ones. 



Cephalosome and anterior segments of the mesosome spinose. 



Metasonie a single plate with minute terminal uropoda. 



Pereiopoda, anterior ones ambulatory, posterior ones defective, very slender and 

 not disproportioually long. 



Pleopoda, first pair opercular. 



The Muuuopsidse (Ilyarachna), to which this genus should be assigned, are 

 notorious for the natatory character of the posterior pereiopoda. A deficiency in 

 this respect of this appendage is, therefore, serious. The genus Ilyarachna seems to be 

 its nearest relation. 



