LYSIANASSA LONGICORNIS. 
87 
Believing that the inferior an ten use are organs adapted 
for the sense of smell, we may conjecture that these 
membranous attachments have the power of increasing 
that faculty to a more acute degree. The fact of their 
being found in the males only would seem to corrobo- 
rate this supposition, since undoubtedly the males seek 
the other sex by the use of this sense, as the following 
experiment appears to demonstrate. Having separated 
a male amphipod from a female, which he was carry- 
ing about with his legs, the latter immediately swam 
to a place of security, but the male dashed eagerly 
round the trough in which they were confined. While 
swimming about, however, we observed that, having 
passed by his mate, he would turn back, and select her 
from among several others. We think that this could 
only have been performed by the agency of smell, and 
therefore consider these calceola as organisms, connected 
with and increasing the capability of that sense in the 
male amphipods where they exist. 
The epistoma projects in a narrow perpendicular wedge- 
like process, with a rounded apex, over which the in- 
ferior antennae bend. 
The mandibles do not materially differ from those of 
species of this genus previously described. The foot- 
jaws have the fifth joint very long, nearly three times as 
long as the sixth, and have squamous plates attached to 
the third and fourth joints ; the plate belonging to the 
fourth joint has the outer margin minutely waved, and 
furnished with a submarginal row of minute cilia, that of 
the third joint reaches to half the length of the fourth, 
and is furnished towards the distal extremity with a 
thick brush of cilia. The first pair of legs are short and 
tolerably robust ; the wrist is about half the length of 
the hand and stouter; the hand from its articulation with 
