MIERS AND HARGER 375 



is an instance of the group in which the flagellum of the 

 second antenna is rudimentary. Sars remarks that in his 

 opinion ' Harger's genus Syiiiclotea [1878] should for the 

 present be retained for the two Arctic species 8. bicuspida 

 and 8. nodulosa [(Kroyer)], both differing distinctly from 

 the form described by Guerin-Meneville — Edotia tuher- 

 cidata — in the well-developed, multiarticulate flagellum on 

 the second pair of antenna^.' 



Cleantis, Dana, 1849, is distinguished by the flagellum 

 of the second antennae being all fused into a single piece, 

 but even this character is sometimes shared by Idotea 

 prismatica. The pleon in Cleantis may consist either of 

 one, two, three, or five distinct segments. The New 

 Zealand species, Cleantis tubicola, Thomson, is eleven times 

 as loDg as it is broad. Mr. Chilton is disposed to regard 

 it as normally not a tube-dweller, though the type-speci- 

 men was found in a tube. The species with all the seg- 

 ments of the pleon fused, such as Cleaniis fiUformis (Say) 

 from the United States, were referred by Dana and Harger 

 to a separate genus, Erichsonia, Dana, 1849. 



On this family the work by Miers already mentioned 

 and Harger's ' Eeport on the Marine Isopoda of New 

 England and adjacent waters ' are essential to the student 

 for the groundwork of his inquiries. 



