259 Fart III. — Seventeenth Annual Report 



Antennce stout, three-jointed, with a very small secondary branch bearing 

 a single seta (fig. 2, PI. XL). The mandibles are small and elongate; the 

 palp is small and consists of a single slender branch bearing two short 

 apical setae (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, PI. X.). Posterior foot-jaws stout, armed with a stout 

 terminal claw and two stout marginal processes (fig. 14, PI. 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 setae of both the outer and inner branches are 

 long and plumose (figs. 3 and 4, PI. XL). The fifth pair of thoracic feet 

 are small and provided with about two moderately long spiniform setae 

 and one or two small hairs (fig. 5, PL XL). 



Habitat. — Brackish water-pools near Fairlie, Firth of Clyde. Appa- 

 rently rare. 



Remarks. — This Copepod at first sight closely resembles Cylindropsyllus 

 Iwvis, Brady, though of somewhat larger size ; but even without dissection 

 the caudal furcse are seen to be distinctly different from those of that 

 species, and if a specimen be dissected several other differences are noticed. 



The antennae, for example, are three-jointed, while in the typical 

 Cylindropsyllus 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 Female. — Body slender, somewhat resembling Cylindropsyllu s 

 Secondary branches of the antennae very small, one-jointed. Mandibl e 

 palp obsolete — in this respect, the mandibles are somewhat similar to 

 those of Maraenobiotus. Maxillae also somewhat similar to those of 

 MaraenobiotuSj 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 three-jointed outer branches; filth 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 setae. 



Leptocaris minutus, sp. n. (PL X., figs. 15-21 ; PL XL, 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 



