259 Part L[L1.—Seventeenth Annual Report - 
Antenne stout, three-jointed, with a very small secondary branch bearing 
a single seta (fig. 2, Pl. XI.). The mandibles are small and elongate; the 
palp is small and consists of a single slender branch bearing two short 
apical sete (fig. 12, Pl. X.). Maxilla short and moderately stout, with the 
apex broadly truncate and armed with a number of strong teeth. The 
palp small, two-jointed, and furnished with a few terminal and subterminal 
hairs (fig. 13, Pl. X.). Posterior foot-jaws stout, armed with a stout 
terminal claw and two stout marginal processes (fig. 14, Pl. X.). The 
inner branches of the first four pairs of swimming feet are all two-jointed ; 
those of the first pair are nearly equal in length to the three-jointed outer 
branches; but in the second, third, and fourth pairs the inner branches 
are considerably shorter than the three-jointed outer branches. All the 
four pairs are moderately stout and are furnished with elongate marginal 
spines, while the terminal setze of both the outer and inner branches are 
long and plumose (figs. 3 and 4, Pl. XI.). The fifth pair of thoracic feet 
are small and provided with about two moderately long spiniform sete 
and one or two small hairs (fig. 5, Pl. XI.). 
Habitat.—Brackish water-pools near Fairlie, Firth of Clyde. Appa- 
rently rare. 
Remarks.—This Copepod at first sight closely resembles Cylindropsyllus 
levis, Brady, though of somewhat larger size; but even without dissection 
the caudal furce are seen to be distinctly different from those of that 
species, aud if a specimen be dissected several other differences are noticed. 
The antenne, for example, are three-jointed, while in the typical 
Cylindropsytlus they are only two-jointed: the inner branches of the 
swimming feet are also more fully developed than they are in Cylin- 
dropsyllus. Such differences may yet render it necessary to remove 
this Copepod to another genus; but, meantime, as no males have yet been 
observed, I prefer to leave it in the genus to which for the present 
it is doubtfully ascribed. 
Leptocaris, gen. nov. 
The HFemale.—Body slender, somewhat resembling Cylindropsyllu s 
Secondary branches of the antennee very small, one-jointed. Mandibl e 
palp obsolete—in this respect, the mandibles are somewhat similar to 
those of Maraenobiotus. Maxillz also somewhat similar to those of 
Maraenoliotus, but the palp is a small cylindrical process with a dilated 
base. Footjaws similar to those of Cylindropsyllus. Inner branches of 
first, second, third, and fourth pairs of swimming feet two-jointed, and 
considerably shorter than the tiree-jointed outer branches; fifth pair very 
small, one-branched. 
The Male.—The male is similar to the female, except that the anten- 
nules are modified and hinged for grasping, and that each of the fifth pair 
of thoracic feet is armed with a stout spine on its inner aspect, in addition 
to a few small sete. 
Leptocaris minutus, sp. n. (PI. X., figs. 15-21 ; Pl. XI, figs. 7-11). 
Description of the Female.—Body elongate and slender. No distinction 
between the thorax and abdomen. Thorax composed of five, and the 
abdomen of four segments (fig. 15. Pl. X.). The first thoracic segment is 
somewhat longer than the entire length of the next two, the second to 
the third are subequal, the fourth and fifth—which are also subequal— 
are rather longer than the second and third. The first abdominal segment 
is about one and a half times longer than the next, the second and third 
are subequal, while the ultimate segment is rather longer than the 
