130 THE ATLANTIC. [cHaP. II. 
At Gibraltar we visited the remarkable caves which pene- 
trate the limestone rock, and on one occasion Captain Nares 
lighted up St. Michael’s Cave, the largest of them, with candles 
and blue-lights, throwing out the magnificent curtains and col- 
umns of semi-transparent stalactite in contrasts of light and 
shade and coloring, and producing a highly picturesque effect. 
We had not time to make any systematic exploration of the 
caves with a view to increasing our knowledge of the animal 
remains which they contain; but His Excellency Sir Fenwick 
Williams, of Kars, the Governor of Gibraltar, with other kind 
attentions, placed at our disposal a considerable collection of 
bones and implements which had been brought together by an 
ofticer formerly stationed at Gibraltar, and we had thus an op- 
portunity of forming some idea of the curious succession of the 
inmates of the caves from prehistoric times down almost to 
our own. | 
We left Gibraltar on the 26th. We had fine, moderate 
weather, and had a very fairly successful week, sounding, trawl- 
ing, dredging, and taking temperatures, between Gibraltar and 
Madeira. 
The trawl was again employed successfully on the 28th, at a 
depth of 1090 fathoms, about ninety miles to the south-east of 
Cape St. Vincent. Several fishes occurred, including an exam- 
ple of Macrurus Atlanticus, and a fine specimen of the rare 
Halosaurus Owen. The trawl on this occasion contained a 
single example of the female of a very large amphipod crus- 
tacean, briefly described under the name of Cystosoma Neptuni 
by Guerin-Méneville, from a single specimen obtained in the 
Indian Ocean. We have since taken several specimens at dif- 
ferent stations in the Atlantic; and as a small male was in one 
case captured in the towing-net, there can be little doubt that, 
like Phronima, to which genus it is allied, Cystosoma is a pe- 
lagic animal, probably retiring during the day to a considerable 
depth, but occasionally coming to the very surface of the water. 
