REPORT ON THE AMPHIPODA. 945 



Boeck says that the palp of the first maxillae has but one joint, armed on the left 

 maxilla with teeth, on the right with spines, and that the palp of the maxillipeds is 

 devoid of the last imguiform joint ; in describing the genus Tritseta, he says that the 

 outer plates of the maxillipeds are armed with few but strong spines, and only on the 

 upper half ; in the present species it will have been noticed that the palp of the first 

 maxillae is two-jointed (though the first joint is rather obscure), and that it has spines, 

 not teeth, on the apex both in the left and right maxilla ; also that the maxillipeds 

 have many small teeth along the greater part of the inner margin, and that the palp 

 has a fourth unguiform joint. Notwithstanding these differences there can be no 

 question of separating the present species from the genus Tritseta ; the spelling of the 

 name is not easy to explain, since Boeck himself derives it from rpiTcua, though he 

 invariably spells it Tritseta. 



From Polycheria tenuijyes, Has well, Polycheria brevicornis, Haswell, Polycheria 

 obtusa, G. M. Thomson, which, as observed above, all belong to this genus, and are all 

 possibly synonyms of Tritseta antarctica, Stebbing, the present species is at once 

 distinguished by the very different side-plates. Haswell figures the maxillipeds of 

 Tritseta tenuipes with a three-jointed palp ; the palp is also, I think, three-jointed in 

 Tritseta dolichonyx, Nebeski, unless the fourth joint be represented by one of the 

 numerous spines at the apex of the third joint. 



Genus Dexamine, Leach, 1814. 



1814. Dexamine, Leach, Edinburgh Encyclopaedia, Crustaceology, Appendix, p 432. 



1815. „ Leach, The Zoological Miscellany, vol. ii. p. 23. 



1815. ,, Leach, Trans. Linn. Soc. Lond., vol. xi. pt. ii. p. 359. 



1816. „ Leach, Encycl. Britanniea, Annulosa, p. 425. 



1825. „ Desmarest, Consid. gen. sur la classe des Crustaces, p. 263. 



1840. Acanthonotus (pars), Milne-Edwards, Hist. Nat. des Crustaces, tome iii. p. 25. 



1851. Dexamine, Costa, in Hope's Catal dei Crost. ItaL, p. 23. 



1851. Amphithonotus, Costa, in Hope's Catal. dei Crost. ItaL, pp. 24, 45. 



1853. „ Costa, Rend, della Soc. r. Borb. 



1857. Dexamine, Spence Bate, Synopsis, Ann. and Mag. Nat. Hist, ser. 2, vol. xix. p. 10 (sep. copy). 



1857. Ampliitlwnotus, Costa, Ricerche sui Crost. Amf. Nap., pp. 175, 195. 



1857. Dexamine, White, Popular Hist, of British Crustacea, p. 177. 



1859. ,, Bruzelius, Skand. Amph. Gamm., p. 78. 1 



1860. „ Boeck, Forh. ved de Skand. Naturf. 8de Mode, p. 658. 

 1862. „ Spence Bate, Brit. Mus. Catal. Amph. Crust., p. 130. 

 1862. „ Bate and Westwood, Brit. Sess. Crust., vol. i. p. 236. 



1864. „ Grube, Beschreibungen einiger Amph. der istrischen Fauna, p. 195. 



1865. „ Lilljeborg, On the Lysianassa magellanica, p. 18. 



1866. ,, Heller, Beitrage zur naheren Kenntniss der Amph. des Adriat. Meeres, p. 30. 

 1868. „ Czerniavski, Materialia ad Zoographiam Ponticani comparatam, p. 111. 



1 Bruzelius, he. cit., p. 79, refers to Montagu's species as " Gammarus speciosus " instead of Gammarus spinosus. 



(ZOOL. CHALL. EXP. — PAUT LXVII. 1887.) XxX 119 



