332 PROF. C. CHILTON ON A NEW AMPHIPODAN 



near to Paradexamine, but it differs distinctly from that genus in the 

 character o£ the mandible, which shows no dentate cutting-edge, spine-row, 

 nor distinguishable molar, and therefore appears to be similar to the 

 mandible of Guernea, a genus distinguished from Paradexamine by the two- 

 jointed palp of the first maxilla, and by other characters. 



In the lower lip, again^ my species resembles Guernea coalita (Norman) in 

 having the principal lobes with an acute apex and the mandibular processes 

 obsolete. There seems to be some approach to this character in Para- 

 dexamine, for in describing P. fissicauda, Chevreux (1906, p. 90) says 

 " Les lobes lateraux de la levre posterieure portent une petite dent au bord 

 interne." This little tooth, however, seems to be rather different from the 

 acute apex to the lobe in the species described below ; in a dissection of one 

 of the specimens of the Paradexamine from the South Orkneys (mentioned 

 above), there is on one side a tooth, ap[)arently as figured by Chevreux, it is 

 narrow and stands out like a little tooth or process from the general out- 

 line of the lobe, and there is a smaller and shorter process situated more 

 proximally on the inner margin; on the other side of the appendage this 

 second process is [)resent, but the other, nearer tiie apex of the lobe, is 

 not apparent in the preparation. 



I have, therefore, decided to establish for iny s}iecies a new genus, which 

 I propose to name Sijndexainiiie, and which may be defined as follows : — 



Syndexaminb, nov. gen. 

 Upper antenna longer than the lower; palp of the raaxillipeds four-jointed ; 

 lower lip with inner lobes well-developed, principal lobes with an acute apex ; 

 mandibular processes obsolete ; mandibles with cutting-edge rounded and 

 entire, no apparent spine-row, nor definite moUir ; palp of first maxilla one- 

 jointed. In other characters, similar on the whole to Paradexamine. 



Syndexaminb carinata, sp. nov. (Plates 26 & 27.) 

 Specific description : — PerjBon robust, dorsally rounded anteriorly, laterally 

 com))ressed and slightly carinate in the last one or two segments. Pleon 

 carinate, segments 1 to 3 each produced dorsally into a strong keel ending 

 posteriorly subacutely ; segment 4 with a dorsal keel on posterior part of the 

 seoment, the dorsal margin of the keel dorsally rounded in front and ending 

 somewhat acutely behind. None of the segments of perseon or pleon pro- 

 duced into dorsal or lateral teeth. Head slightly longer than the first and 

 second segments of the perseon combined ; dorsal surface convex so that the 

 anterior part is depressed ; rostrum very short and blunt at apex. Pleon 

 segment 3 with postero-lateral' angle acute and slightly produced ; the 

 combined 5th and 6th segments bearing a group of three or four stout 

 spinules at the base of the telson, and one lateral spiuule more anteriorly and 



