160 



Miss H. Richardson on the Isopods of the 



strong immovable finger, irregular in shape, liaving 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. 



b. Ui'opoda with one of the branches almost 

 obsolete oi- rudimentary, not lamelliform. . 

 V . Uropoda witli 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 cuttiug-edges meeting 

 squarely behind the large upper lip ; 

 the secondary plate and peculiar equi- 

 valent foi the molar well developed. 

 First maxillpp having the plate of the 

 first joint armed with three spines, 

 that of the third with many. Second 

 maxillpe of moderate size, the three 

 free plates very setose. Maxillipeds 

 with the palp rather broad, very setose. 

 d'. Mandibles with the distal part produced 

 into a long prominent process, the 

 pair nnich overlapping ; the secondary 

 plate and molar evanescent. First 

 maxilht having the plate of the first 

 joint unarmed, of the third carrying 

 one very long spine. Second maxillae 

 small and feeble, the free ])lates almo.*t 

 rudimentary, with few seta?. Maxilli- 

 peds with tlie palp narrowed, not very 



setose 



c. Maxillipeds with the palp embracing the 

 cone formed by the distal parts of the 



II. LlMNORIID.«. 



III. CiROLANIDiB. 



IV. CORALLANIDJB. 



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

 of the Cirolanidaj (Videnak. Selsk. Skr. tith ser , natur. og math" Afd. v. 

 1890, p. 317), as translated by Stebbing, Hist, of Crust. 18i>.'^, pp. 340, 341. 



