138 Messrs. T. and A. Scott on some 



first joint is considerably longer than any of the others, the 

 second to the fifth joints gradually decrease in length, while 

 the penultimate joint is about one third of the length of the 

 preceding one and half the length of the next; the formula 

 shows the proportional lengths of the joints — 



15 ■ 11 . 9 ■ 7 . 6 ■ 2 . 5 

 1 2 3 4 5 6 7" 



In the male antennaj the third and fifth joints are much shorter 

 than either of the joints that precede or follow them, and the 

 sixth and seventh, which are subequal, are each fully twice 

 the length of the fifth. Posterior antennge nearly as in 

 Amymone sphcerica. Mandibles and maxillae also somewhat 

 similar to those of that species, but the second joint of the 

 mandible-palp is proportionally considerably longer, while 

 the mandible is armed with longer apical teeth. The anterior 

 foot-jaws are provided with a claw-like terminal spine, and 

 the marginal process at the base of the last joint bears two 

 spiniform terminal setse. The posterior foot-jaws resemble 

 those of Amymone sphfey-ica^ but the interior edge of the last 

 joint is not so densely fringed with hairs. The outer branches 

 of the second and third pairs of swimming-feet are two-jointed 

 (fig. 4), and of the fourth pair three-jointed; the first joint 

 of the outer branches of the fourth pair is much shorter than 

 either the second or third joints, and a strong spiniform seta 

 springs from the inner edge and near the middle of the last 

 joint ; the length of this spiniform seta is at least equal to 

 the whole of the outer branch (fig. 5) ; the first and second 

 joints of the inner branches are nearly of equal length and 

 sliorter than the last joint ; the only setai on the inner 

 branches of the fourth pair are — one on the inner margin near 

 the distal end of the second joint, and three (two terminal and 

 one subterminal) on the last joint. The basal joint of the 

 fifth pair in the female is broadly foliaceous, the inner margin 

 is rounded and bears three short plumose setse, while the apex 

 is somewhat oblique and angular and armed with two stout 

 spiniform setse ; the secondary joint is narrow and extends to 

 the apex of the basal joint, and is furnished with three stout 

 hairs on the outer edge and a small terminal hair. The 

 male fifth foot has no secondary joint, it is long and very 

 narrow and slightly curved, and furnished with three marginal 

 and two terminal setse ; one of the terminal setse is much 

 longer than the other. Colour irregularly diffused, dark 

 cinereous, nearly black in some parts, as at the posterior end. 

 Hah. Cromarty Firth, near Invergordon, frequent. The 



