AMPHIPODA OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 213 



identified with Atylus monoculoides Haswell. In 1909 I urged reasons for uniting 

 with it the third species also, i.e. E. 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 E. crassi, said : " Whether this can be retained as a species 

 distinct from E. 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 E. csesaris, or may be altogether 

 absent, as in the specimens now before me. This variation has already been referred to 

 by Stebbing, Walker, Chevreux, and myself, and need not be further discussed. 



Along with some of the specimens which he described under the name " E. csesaris 

 Stebbing, var." Walker found an ovigerous female, 5 mm. long, which with some hesita- 

 tion he described as a new species, E. orchomenopsis, the main difference being that in 

 the third uropoda the 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. 



Pontogeneia danai (G. M. Thomson). 



Ati/lus danai G. M. Thomson, 1879, p. 238, pi. s.c, fig. 1. 



„ lipinis Haswell, 1880, p. 328, pi. xx. fig. 1. 

 Eusiroides lippus Stebbing, 1906, p. 346. 

 Pontogeneia danai Stebbing, 1906, p. 360. 

 „ Chilton, 1912, p. 130. 



Falkland Islands, Cape Pembroke, Station 118 ; among calcareous algse. 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 antennae with certainty, but others better preserved 

 show that they differ from the next species in having every fourth or fifth joint of the 

 flagellum of the upper antennae produced below and crowned with a tuft of sensory 

 setse ; in P. aiitarctica 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 antennas are more nearly equal in length, the gnathopoda 

 are more slender, and the telson is perhaps rather more deeply cleft. The 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 setae 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. 



(ROY. SOC. EDIN. TRANS., VOL. SLVIII., 495.) 



