750 DE WALTER E. COLLINGE. 



panded, third short and wide, third and fourth subequal and deeply indented distally 

 on the ventral side ; flagellum with three or four joints in the male, female usually 

 unjointed. First maxillae (fig. 109) with outer lobe terminating in four stout curved 

 spines and three toothed and one small one, inner lobe with three long setose spines. 

 The segments of the mesosome (fig. 112) are slightly depressed, the pleural plates of 

 the first extending forwards and partly flanking the cephalon. Coxal plates of the 

 second to fourth segments very narrow and not extending over the whole of the 

 lateral margin, fifth and seventh much wider, forming the entire lateral margin with 

 the posterior angles produced into an elongated point. Maxillipedes (fig. 110) 

 elongated, palp five-jointed, with well-marked groove on the third joint, epipodite 

 wide and long, distal inner lobe pointed distally. Thoracic appendages (fig. Ill) 

 fairly robust. Metasome (fig. 113) with three short segments and lateral indications 

 of a further coalesced one, terminal segment with lateral margins straight and pos- 

 teriorly elevated, folding over on to the dorsal side, posterior margin rounded. 

 Uropoda (fig. 114) wider anteriorly than posteriorly, setose on the inner and outer 

 lateral margins, endopodite narrower than the basal plate. 



Length 13*5 mm. 



Colour (in alcohol) variable. 



Geographical Distribution.- — Firth of Clyde, south and south-west coast of England 

 (Stebbing) ; Jersey (Sinel) ; west coast of France (Dolleus) ; Adriatic Sea (Claus) ; 

 Mediterranean (Issel). 



Remarks. — This species has been very fully described by Issel (35), who has 

 given outline figures of the animal and various appendages. In addition to correct- 

 ing Bate and Westwood's description and figures, he has pointed out that there is 

 considerable variation in the flagellum of the antennas of the female. Three of his 

 figures are here reproduced illustrating this (figs. 106-108). 



3. Genus Synisoma, nov. nom. =Stenosoma, Auctt. 



Body oblong, widening slightly towards the middle of the length of the meso- 

 some, usually keeled, surface smooth, tuberculated or sculptured. Cephalon with 

 well-developed lateral lobes. Antennulae with first joint expanded, flagellum com- 

 posed of a single joint. Antennae with large second joint, flagellum multiarticulate, 

 style short. Palp of maxillipede four-jointed, distal inner lobe usually wide. 

 Segments of the mesosome keeled or raised, pleural plates of the first segment 

 produced laterally or forwards. Coxal plates small, but visible dorsally on all 

 segments excepting the first. Appendages somewhat slender. Metasome composed 

 of a single segment, with lateral sutures indicating coalesced segments ; terminally 

 the segment is usually pointed. Uropoda flattened, endopodite more or less tri- 

 angular in shape. 



Dollfus (20) wrongly confounded the genus Synidotea, Harger, with this genus. 



