CRUSTACEA FROM THE FALKLAND LSLANDS. 355 



AMPHIPODA. 



Tribe GAMMARIDEA. 



Fam. Lysianassid^e. 



1874. LysianassldcK Bacliholz, Zweite D. Nordpolarf. vol, ii. 



p. 299. 

 1913. „ Clievreux, Deuxieiue Exp. Aiitarct. fiangaise, 



p. 87. 



Gen. Tryphosites Sars. 



1891. TnjplLOsltes Sars, Crust. JSTorway, vol. i. p. 81. 



1906. „ Htebbing, Da.s Tierieieli, vol. xxi. p. 77. 



1911. „ Sexton, Ann. Nat. Hist. ser. 8, vol. vii. p. 510. 



1912. „ Chilton, Tr. Roy. Soc. Edinb. vol. xlviii. pt. 2, 



p. 469. 

 To receive the new species here referred to this genus, its 

 definition must be a little modified, by withdrawal of the state- 

 ment that the postero-lateral angles of the third pleon segment 

 are acutely upturned, nor does the shape of the hand in the 

 second gnathopod precisely conform with that in the type species. 

 Also the inner ramus of the second uropod is not constricted. 



Tryphosites chevreuxi Stebbing. (PI. III.) 

 Abstract P. Z. S. 1914, p. 30. (April 28.) 



The third pleon segment, instead of having the postero-lateral 

 corners upturned with a smooth concave margin above, has the 

 lower half of the postero-lateral margin convex and cut into 

 a serration of nine little teeth. Thus the species is sharply dis- 

 tinguished both from I", longipes (Bate & West wood) and from 

 JIoploHi/x stehbingi Walker, 1903, which Chilton in 1 9 1 2 transf ei-ed 

 to Tryphosites, with the i-emark, among others, that it " appears 

 to be very close to T. longipes of northern seas, diflering chiefly 

 in having the perseopoda shorter and stouter and the eyes in- 

 distinct." Walker lays some stress upon " the absence of a 

 depression " dorsally in the fourth pleon segment. Such a de- 

 pression is sometimes masked by the telescoping of the segment. 

 In the new species the depression is very marked. 



Eyes obscure or absent. Both pairs of antennte strongly 

 resembling those of 2\ longipes. Accessory flagellum in first pair 

 of the male 7-jointed, principal with 16 joints, some of which 

 carry small calceoli. Flagellum of second pair not so long as the 

 body, with 32 joints, several of the alternate ones carrying cal- 

 ceoli, decreasing in size on the distal portion. Mouth-organs in 

 close agreement with those of 1\ longipes. 



The gnathopods differ from those of the two earlier species in 

 scaicely anything but the hand of the second pair, which is not 



Proc. Zool. Soc— 1914. No. XX lY. 24 



[15] 



