1410 THE VOYAGE OF H.M.S. CHALLENGER. 



Euthemisto gaudichaudii (Guerin) (Pis. CLXXIL, CLXXIIL). 



1828. Tliemisto Gaudichaudii, Guerin, Mem. de la Soc. d'Hist. nat. de Paris, t. iv. pi. xxiii. 

 1830. „ Milne-Edwards, Ann. d. Sci. Nat., t. xx. p. 393 (extr., p. 42). 



1836. „ „ Guerin-Meneville, Iconographie du Regne Anim., t. ii. pi. xxv. 



fig. 7. 

 1838. „ ,, Milne-Edwards, Hist. nat. des Anim. sans vert., t. v. 



1840. „ „ Milne-Edwards, Hist. nat. des Crust., t. iii. p. 84. 



1840. „ „ Lucas, Hist. nat. des Crust., des Arachn. et des Myriap., p. 235, 



pi. xviii. fig. 5. 

 1862. „ „ Spence Bate, Brit. Mus. Cat. Aniph. Crust., p. 314, pi. iv. fig. 10. 



1862. „ Guerinii, Spence Bate, Brit. Mus. Cat. Amph. Crust., p. 313, pi. i. fig. 9. 



1887. Euthemisto Gaudichaudi, Bovallius, Systematical List of Amph. Hyper., Bihang till 



K. Svensk. Vetensk. Akad. Handl., Bd. 11, No. 16, p. 21. 

 1887. „ „ Bovallius, Arctic and Antarctic Hyperids, Vega-Exped., Bd. iv. 



p. 568. 



Back little compressed, and not dorsally dentate. Second segment of the perseon the 

 shortest ; the first three segments of the pleon with the lower margin slightly serrate, the 

 posterodateral angles produced very slightly into acute points. 



Upper Antenna}. — First joint of the peduncle longer than broad, the two following 

 joints very short ; the flagellum much longer than the peduncle, tapering, having a 

 serrate inner margin and about a dozen pairs of filaments on the inner side, the end 

 narrow, curved. 



Loiver Antenna}. — Third (first free) joint of the peduncle not longer than broad, the 

 fourth longer than the third, and the fifth than the fourth ; the flagellum slender, 

 tapering, longer than the peduncle, either consisting of one long joint, or with a long 

 first joint followed by a few or several short joints. 



Upper Lip about as broad as its depth, unsymmetrically bilobed, one side of the 

 distal emargination more oblique than the other. 



Mandibles. — The cutting plate with fourteen little teeth, of which the lowest is the 

 largest, standing a little apart from the rest ; the secondary plate of the left mandible 

 has an extremely narrow neck, with a front edge about two-thirds the width of that of 

 the principal plate, against which it is so closely applied that the twelve little teeth are 

 not easy to count ; the right mandible is without a secondary plate, and on the principal 

 plate the lowest tooth and the lowest but one are larger than the rest ; behind the cutting 

 plates there is a large bunch of spines, some of which are almost hair-like ; the molar 

 tubercle is large and prominent, with the usual rows of denticles, the row on the inner 

 margin of the crown containing more than twenty teeth stouter than those on the surface 

 of the crown, and attended each by a setule ; the palp is placed on a little raised base 

 which sometimes looks like an incipient joint ; the palp itself is long and slender, the 

 first joint shorter thaji the third, the two together about as long as the second, which is 

 more or less bent, more in large specimens than in small ; the third joint is apically acute. 



