AMPHIPODA OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 495 
identified with Atylus monoculoides Haswell. In 1909 I urged reasons for uniting 
with it the third species also, z.e. HL. crassi, and pointed out the identity of the whole 
with Bovallia gigantea. 
About the same time STEBBING independently examined additional specimens from 
Australia, and, speaking of F. crassz, said: ‘‘ Whether this can be retained as a species 
distinct from L. monoculoides seems doubtful.” 
The amount of serration on the posterior margin of the third pleon segment may be 
considerable, as in the form described under the name LH. cesaris, or may be altogether 
absent, as in the specimens now before me. This variation has already been referred to 
by Sressinc, WALKER, CHEVREUX, and myself, and need not be further discussed. 
Along with some of the specimens which he described under the name “ #. cxsaris 
Stebbing, var.” Waker found an ovigerous female, 5 mm. long, which with some hesita- 
tion he described as a new species, L. orchomenopsis, the main difference being that in 
the third uropoda tlie outer branch is much the longer and has a terminal joint. Mr 
WALKER is disposed to think that, though sexually mature, this specimen has not 
attained the full mature characters. 
Genus PontoGENEIA Boeck, 1871. 
Pontogenera dana (G. M. Thomson). 
Atylus danai G. M. Thomson, 1879, p. 238, pl. x.c, fig. 1. 
,  ltppus Haswell, 1880, p. 328, pl. xx. fig. 1. 
Eusiroides lippus Stebbing, 1906, p. 346. 
Pontogeneia danat Stebbing, 1906, p. 360. 
‘ », Chilton, 1912, p. 130. 
Falkland Islands, Cape Pembroke, Station 118; among calcareous alge. January 
1903. Several specimens, some poorly preserved, the largest 6 mm. long. 
Some specimens appear to have been partially dried, and it is not easy to make 
out the necessary points in the antennz with certainty, but others better preserved 
show that they differ from the next species in having every fourth or fifth jomt of the 
flagellum of the upper antenne produced below and crowned with a tuft of sensory 
sete; in P. antarctica every third joint is dilated to a less extent. In both species 
the dilatations are closer together on the six or seven basal joints of the flagellum. 
In the present species, too, the antenne are more nearly equal in length, the gnathopoda 
are more slender, and the telson is perhaps rather more deeply cleft. ‘he differences— 
particularly the one last mentioned—are all rather slight. 
I have been able, since the above paragraph was written, to compare the Falkland 
Island specimens with specimens of P. danai G. M. Thomson from New Zealand, and 
think they must be considered the same. In the Falkland Island specimens the 
peduncle of the upper antenna bears rather longer setee on the under surface, but it 
also bears on that surface a number of calceoli on slight projections, giving a scabrous 
appearance which is well marked in the New Zealand specimens. 
TRANS. ROY. SOC. EDIN., VOL. XLVIII. PART II. (NO. 28). 74 
