160 



Miss H. Richardson on the Isopods of the 



strong immovable finger, irregular in shape, having its 

 central portion raised and truncate on its upper surface, whic'i 

 is distinctly serrate. The dactylus is likewise serrate on its 

 inner surface. The other legs are slender, with a gradual 

 increase in stoutness. 



Colour brown, marked in some specimens with a darker 

 brown, and having oval patches of the darker colour on 

 the head. 



Kyska Harbour, Alaska ; Mr. W. H. Dall collector ; depth 

 6 to 8 fathoms. 



Type. No. 22563, U.S. N. M. 



II. FLABELLIFERA. 



Analytical Key to the Families of Flahellifera, 



a. Pleon consisting of six segments. 



h. Uropoda with one of the branches ahnost 

 obsolete or rudimentary, not lamelliform . . 

 V . Uropoda with both branches developed ; 

 mostly lamelliform. 

 c* Maxillipeds with the palp free, the mar- 

 gins of the last two joints more or less 

 setose, never furnished with hooks. 

 d. Mandibles with the rather broad, more 

 or less tridentate cutting-edges meeting 

 squarely behind the large upper lip ; 

 the secondary plate and peculiar equi- 

 valent for the molar well developed. 

 First maxillae having the plate of the 

 first joint armed with three spines, 

 that of the third with many. Second 

 maxillse of moderate size, the three 

 fi-ee plates Tery setose. Maxillipeds 

 with the palp rather broad, very setose. 

 d'. Mandibles with the distal part produced 

 into a long prominent process, the 

 pair much overlapping ; the secondary 

 plate and molar evanescent. First 

 maxillae having the plate of the first 

 joint unarmed, of the third carrying 

 one very long spine. Second maxillae 

 small and feeble, the free plates almost 

 rudimentary, with few setae. Maxilli- 

 peds with the palp narrowed, not very 



setose 



c'. Maxillipeds with the palp embracing the 

 cone formed by the distal parts of the 



II. LlMNOBIID-S. 



III. CrROL,AmD.ffl;, 



IV. CoBALLANID.ffi:. 



* The four points following V are taken from Hansen's analytic key 

 of the Cirolanidae (Vidensk. Selsk. Skr. 6th ser., natur. og math. Afd. v. 

 1890, p. 317j, as translated by Stebbiug, Hist, of Crust. 189.3, pp. 340, 34L 



