148 Transactions. 
long divergent sete. This appendage to the second maxilla appears to be 
the homologue of a similar appendage to the second maxilla of Tanais, as 
described by Fritz Muller* and figured by Dr. MacDonald.t 
The mawillipedes (pl. XVIII, fig. 6) are rather long: the first joint is short, 
the next is much larger and longer and, I believe, bears an appendage. 
The third joint is broader than long, while the fourth is much longer than 
broad and has the inner side fringed with sete. The two terminal joints 
are seen partially in profile in fig. 6, but in fig. 6a. they are seen full on; 
they both bear several long sete, each of which is serrated on one side only. 
The first thoracic segment is so closely joined to the head that the line 
of junction cannot be seen; the second thoracic segment is more closely 
united to the ‘‘ carapace” thus formed than the other thoracic segments are 
to one another. 
In the other species of Apseudes the eyes are pedunculated like those of 
the Podophthalmous Crustacea, but in this species they are very small, and 
there is no sign of any peduncle. 
The first pair of gnathopoda (pl. XVIIL., fig.7) are very large. The carpus 
and propodos are the two largest joints, the propodos being especially large; 
it is produced into a strong blunt finger, which has a rounded prominence 
at the middle of its inner side, and bears several short stiff-looking sete at 
the end. The movable finger is strong, curved, tipped with brown at the 
end, and somewhat roughened on the inside. In conjunction with the 
fixed finger it forms a very powerful chela. 
In all other species of Apseudes that I know of, the propodos of the 
second gnathopod is transversely dilated; this is, indeed, given by Mr. Spence 
Bate as a generic character, but in my species the second gnathopod (pl. 
XVIII., fig. 8) differs from the other thoracic legs only in being very slightly 
larger. The carpus is broader than the propodos ; both bear stout spines 
on their inner edge, and there is one spine and two or three long hairs at 
the base of the terminal finger. The third pair of thoracic legs differ from 
the second only in being very slightly smaller and in having a few more 
spines and hairs. The hairs are plumose. Fig. 9a shows the arrangement 
of these spines and hairs. The succeeding legs are of the small general 
shape, but the spines gradually disappear, until in the last pair (fig. 10) 
there are none at all; the terminal finger also differs in having pro- 
minences on its inner edge. 
The pleon is very short. I have not been able to make out the divisions 
between the segments, but it is evident that the first five segments must be 
* “ Facts and Arguments for Darwin," p. 17. 
f “On the External Anatomy of Tanais vittatus."—Transactions of the Linnzan 
Society, Second Series, Zoology, vol. i., p. 67, pl. xv., fig. vi.d. 
