AMPHIPODA. 
37 
The most noticeable character of this species is (as the name implies), the great 
length of the lower antennae, especially in the male. 
FAM. SEBIML nov. 
Body rather slender, subdepressed; side-plates moderately deep. 
Antennse subequal, rather short. 
Mandibles with a toothed cutting edge, molar tubercle obscure, palp gather small, 
three-jointed. 
Maxillipeds with small inner and outer plates, palp well developed. 
First gnathopods chelate in the females, chelate or subchelate in the males. 
Second gnathopods longer than the first, perfectly chelate. 
Third uropods uniramous. 
Telson entire. 
The genus Seba has been successively allotted to “ the confines of the family 
Leucothoidse (G. 0. Sars),” Stebbing, p. 783 ; the Lysianassidse, Della Valle, p. 773* ; 
and the Corophidse, Chevreux,f p. 111. As none of these positions is satisfactory, 1 
have thought it better to establish a new family for it. As for the genus, it appears to 
me extremely doubtful whether the original species ( S. innominata, A. Costa, of Sp. 
Bate, Brit. Mus. Cat., p. 159), as described by him, ever existed ; it was repudiated by 
A. Costa. I propose, therefore, to call it Seba, Stebbing, 1875, with Seba saundersi, 
Stebbing, as the type. 
Seba Antarctica. (PI. 13, fig. 22.) 
Seba antarctica, A. 0. Walker, Ann. and Mag. Nat. Hist. XVIII. (1906), p. 151. 
Common in sponges at Hut Point. /7 o 
The females of this species agree in the smallest detail with the very careful and 
accurate description of Seba saundersi, Stebbing, in the ‘ Challenger ’ Report, and I have 
very little doubt that it is identical. For reasons given elsewhere,! however, it is 
impossible, in the absence of the description of the male from the same locality as 
S. saundersi (off Cape Virgins, Patagonia), to be certain of this. 
For the description of the female I refer to that of S. saundersi above mentioned. 
The males appear to be dimorphic; the commoner form is only to be distinguished 
by the absence of the incubatory lamellae. In one gathering, however (W.Q., 19 Mar., 
1902, 10 fm.), two male specimens, measuring respectively 7 mm. and 5 mm., occurred ; 
the length of females with ova and small males being 4’25 mm. In addition to their 
larger size, these were remarkable for having the meral joints of the last three pairs of 
peraeopods greatly expanded behind, especially in the larger of the two. 
* Fauna and Flora d. Golfes v. Neapel. Gammarini, p. 773. 
f Amphipodes provenant des Campagnes de l’Hirondelle (1900), p. 111. 
t Ann. and Mag. Nat. Hist. XVII. (1906), p. 569. 
