120 DUBLIN N A TiniAL HISTORY SOCTETT. 



to any other I am acquainted with. It probably forms with it, as sug- 

 gested in my memoir on the British Diastylidae ('Annals, Nat. Hist./ 

 1856), a genus distinct from Cuma, and which may be readily distin- 

 guished by the character oi the Jive segments of the ^emow being per- 

 fectly developed posterior to the carapace, whereas in Cuma there are 

 hut four thus developed. 



"Although I have not had an opportunity of dissecting a typical 

 species of the genus Cuma, I do not hesitate to group the present species, 

 and probably C. JEdwardsn, as distinct from Cuma, since Goodsir asserts 

 that both antennse are present in those Cumse which he examined, the 

 upper in a rudimentary state, a character which I cannot find in V. oris- 

 tata ; this, taken with the altered condition of the pereion, justifies the 

 presumption of a generic distinction. 



'' In selecting a name, I have fixed on that of the discoverer, being 

 one which is familiar to every carcinologist, and to which honour is due 

 for valuable discoveries in this department of zoology. More than one 

 of the name having been eminent as a naturalist, a license has been 

 taken, — the Christian name has been incorporated with the surname, 

 and both spelled according to sound : the word is thus both shortened 

 and rendered more easy for pronunciation by foreigners. 



Cyeianassa longicoenis {J. F. Thompson, MSS. sp.). 



" Pleopodis, paribus prime et sexto exceptis, nuUis. Ceteris ut Cpr, 

 gracilis. 



"No pleopoda developed on the second, third, foxirth, and fifth seg- 

 ments ; the other characters as C. gracilis. 



" All the appendages of the pleon are suppressed, except the first and 

 sixth pairs ; telson squamiform and rudimentary. 



"Length, -15 inch. 



