A REVISION OF THE BRITISH IDOTEID^E. 735 



the following genera : — Glyptonotus, Eights ; Chaetilia, Dana ; Arcturides, Stucler ; 

 Idotea, Fabr. ; Edotia, Guerin-Men. ; and Cleantis, Dana. Norman (47), 1904, 

 mentions only the three British genera, whilst Richardson (58) in 1905 arranged 

 the genera as follows : — Mesidotea, Richardson ; Chiridotea, Harger ; Idothea, Fabr. ; 

 Pentidotea, Richardson ; Synidotea, Harger ; Colidotea, Richardson ; Edotia, Guerin- 

 Men. ; Eusymmerus, Richardson ; Erichsonella, Benedict ; and Cleantis, Dana. 

 In the present communication I propose to divide the family as follows : — 



Fam. IDOTEIDiE, Leach, 1813. * 



Sub-fam. i. Idotedsle, Miers, 1881. 



Genus 1. Idotea, Fabr., 1798. 



(l) Idotea baltica (Pallas). 



(2) , 



, pelagica, Leach. 



(3) , 



, neglecta, G. 0. Sars. 



(4) , 



, emarginata (Fabricius). 



(5) , 



, granulosa, Rathke. 



(6) , 



, sarsi, n. sp. 



(7) , 



, viridis (Slabber). 



(8) , 



, metallica, Bosc. 



(9) , 



, linearis (Pennant). 



Sub-fam. ii. 

 Genus 2. Zenobiana, Stebbing, 1895. 

 (l) Zenobiana prismatica (Risso). 



Sub-fam. iii. 



Genus 3. Synisoma, nov. nom. 



(1) Synisoma lancifer (Leach, MSS.). 



(2) ,, acuminata (Leach). 



Fam. Idoteid^e, Leach, 1813. 



Body ovate, oblong or elongate, and more or less depressed. Cephalon and 

 mesosomatio segments distinct; coxal plates separate from or confluent with the 

 segments ; metasome with some or all of the segments consolidated into a terminal 

 scutiform piece. Eyes usually dorso-lateral, occasionally dorsal, multifaceted. 

 Antennules with three-jointed peduncle, fiagellum uniarticulate. Antennae with 

 five-jointed peduncle, fiagellum usually multiarticulate, but may consist of a single 

 joint or may be short or rudimentary. Mandibles without palps. First maxillae 



* Given on the authority of Agassiz, Nomenclator Zoologicus. 



