65 
the fourth, as long as or rather shorter than the third,” both 
of which alternatives are alien to the present genus. From 
Eudromia, Henderson, with which Exodromia agrees in regard 
to the fourth and fifth legs, it is separated by having the frontal 
region tridentate and normal, by the shortness of the chelipeds, 
and their sexual differentiation, as well as by the strongly- 
tubercled carapace. 
Exodromidia spinosa (Studer). 
Plate XVIII. 
1883. Dromidia spinosa, Studer, Crustacea of the Gazelle, 
Abhandl. K. Akad., Berlin, 1882, p. 22, Pl. 1, figs. 
£O: a, D: 
Only the female of this species was described by Studer, but 
his description in almost all respects applies to both sexes. 
He speaks of the carapace as completely covered with fine down, 
having among it solitary short sete. In all our specimens the 
fine down is absent from many parts of the carapace and limbs. 
Studer also speaks of the tridentate front as having the middle 
tooth small, pointed, downward bent, and the side teeth large, 
three-sided, strongly produced forward. It might be proper 
to say that the middle tooth is on a lower plane than its larger 
companions, rather than that it is downward bent, for its direc- 
tion seems to be horizontal. The outer orbital angle is defined 
by a very small tooth, with a rather larger one near it on the 
lower margin. The antero-lateral margin has three forward 
pointing teeth, of which the middle one is a little the most 
prominent, and the lowest bounds the branchial (or second 
cervical) furrow. A row of small denticles commencing on the 
hind margin of the third tooth is continued some way backward, 
but is often lost to view among the down and sete. At the 
middle of the carapace there is a large transverse tubercle, or 
in small specimens a simply conical one, probably bounding 
the gastric region. In front of it there is an inconspicuous 
tubercle, not mentioned by Studer, and probably not visible 
when the down is present on that part of the carapace. At 
some distance on either side of this, but a little to the rear, 
there is a tubercle on each hepatic region. Within the cardiac 
region there is a large conical tubercle, and one of about the 
same size at some distance on either side of it. Finally, on the 
intestinal region there is a large transverse tubercle or promin- 
ence. 
