252 



Part III. — Thirteenth Annual Report 



fifth and sixth, which are shorter than the others ; the first and second 

 joints are densely covered with small hairs on the upper aspect, — 

 especially the first joint; the proportional lengths of the joints are as 

 follows (see also fig. 14) : — 



Proportional lengths of the joints , 14 • 10 • 10 • 9 • 6 • 7 • 9 ) 

 Number of the joints, 1* 2 • 3 ■ 4 * 5 • 6 * 7 



Antennas stout, secondary branch very small, one-jointed. Mandibles 

 stout, the broad citing part is armed with three strong blunt teeth and 

 a few small spines, there is also a papilliform lateral process, as shown 

 by the drawing (fig. 17); mandible-palp very small, one-jointed, and 

 furnished with one terminal and three lateral setae. Anterior foot-jaws 

 dilated, short, armed with a stout terminal claw and two marginal 

 spiniferous processes. Posterior foot-jaws are less robust, and consist of 

 two moderately long and nearly equal joints, and a very small terminal 

 joint which forms the base of a moderately stout but not very elongate 

 claw ; the margins of the second joint are ciliated, and a setiferous spine 

 springs from the upper distal angle of the first joint. The first pair of 

 swimming feet have both branches three-jointed, the joints of the outer 

 branches are subequal, and armed with strong spines at the outer distal 

 angles ; the first joint of the inner branches reaches to about the 

 extremity of the outer branches ; the second and third are shorter and 

 subequal, their combined length being scarcely equal to the first joint 

 (fig. 21). Outer branches of the second, third and fourth pairs elongate, 

 and composed of three subequal joints ; inner branches very short, 

 two-jointed ; in the second pair, the inner branches extend a little beyond 

 the second joint of the outer branches ; in the third pair, the inner 

 branches extend to about the middle of the second joint of the outer 

 branches, while in the fourth pair, the inner branches are still shorter, 

 and do not extend much beyond the first joint of the outer branches (fig. 

 22). The fifth pair has the produced inner portion of the basal joint 

 broadly subcylindrical, the rounded extremity is provided with six 

 moderately long setae, but the principal apical setae is about twice as long 

 as the one on either side of it; secondary joint small, subovate, and 

 furnished with six setae, arranged round the outer margin and end, the 

 middle apical setae being much longer than any of the others. Caudal 

 stylets very short (fig. 26). 



Male. — Antennules indistinctly eight-jointed, and strongly hinged ; the 

 third and fourth joints are very short but considerably dilated laterally, 

 and the seventh and eighth form together a claw-like apex. Mouth 

 organs and swimming feet similar to those of the female, except that the 

 third pair are somewhat distorted, the first and second joints of the outer 

 branches are dilated, while the third is small and armed with two strong 

 terminal and two lateral spines — the inner apical spine being very large ; 

 the inner branches are composed of three small joints (fig. 23). The 

 basal joint of the fifth pair is not much produced and broadly rounded, 

 and carries two short but very stout blunt-pointed spines and a minute 

 seta ; the secondary branch is very small and provided with three setae 

 (fig. 25). 



Habitat. — Lochs in Barra and North Uist, Outer Hebrides. In lochs 

 in the Shetland Islands, and in shore-pools near the head of West Loch 

 Tarbert, Argyllshire. 



Remarks. — Cantliocamptvs liirticornis appears to be widely distributed 

 throughout the Hebridian islands and in Shetland, but is apparently rare 

 on the Mainland. The structure of the first feet resembles that of the 

 first pair in Canthocamptus trispinosas, Brady, but the antennules, which 

 are only seven-jointed, and the form of the fifth feet in male and female, 



