248 Rev. Canon A. M. Norman on British Mysidse. 



as wide, only slightly longer than peduncle of antennules ; 

 outer margin without any spine, but naked (that is without 

 setae) on the lower half ; from the spot where the setae com- 

 mence the margin slopes inwards to the narrowly rounded 

 point, which is subcentral to the length of the scale. Legs 

 rather slender ; tarsus of 4-6 articulations, the last very 

 slender and terminating in a very slender nail. Telson much 

 shorter than inner uropods, gradually narrowing, cleft about 

 one fourth its length, widely open ; upper half of sides of 

 telson without spines, distal half with 6-12 lateral spines, the 

 penultimate of which is some distance from the extremity ; 

 terminal spines more than usually developed and long, their 

 length often equal to about half the depth of the cleft. Inner 

 uropods with 6-10 spines on the inner margin, gradually in- 

 creasing in length distally and confined to the anterior two 

 thirds of the margin ; otolith of moderate size. 



Male. — Pleopods of first two pairs simple ; third pair with 

 large and broad basal joint and a single one-jointed ciliated 

 branch, which gives off a small laterally projected process on 

 the outer side of its base : fourth pair very long, consisting 

 of two basal joints, the second of which is long, and two 

 branches ; of these the inner is minute, two-jointed, the first 

 giving off a little lateral process, the second terminating in 

 three setse ; outer branch of great length, basal portion com- 

 posed of five articulations, of which the first is nodulous below 

 at the extremity, and the third and fourth are subequal in 

 length ; the limb terminates in two long filaments, which are 

 ciliated towards the extremities, and the outer about half as 

 long again as the iiiner : fifth pair formed for swimming, of 

 considerable length, reaching to half the length of telson ; 

 basal joint long, branches 4-5-jointed, furnished with longsetae; 

 inner branch with a small lateral projection at the base. 

 Length 8-10 millim. 



Hemimysis Lamornce is a true Hemimysis^ agreeing in all 

 generic characters with the type H. abyssicola, from which 

 indeed it seems to be chiefly distinguished by its more robust 

 form and fewer lateral spines on the telson. It agrees with 

 that species in the broad flattened second joint of the man- 

 dible-palp, in the slender nails in which the legs terminate, 

 in the narrow outer uropods, abruptly truncate at the extre- 

 mity, and above all in the characters of the pleopods in the 

 male. Prof. G. O. Sars, pi. xxx. fig. 13 (Mon. Norges Mys.), 

 figures the fourth pleopod of the male j but, as he correctly 

 states, it must be " maris junioris," since it is very different 

 from that of the adult. 



