Rev. Canon A. M. Norman on British Mydidie. 259 



joint, in the anterior pairs eom])osed of four to five articula- 

 tions, of whicl) the first (as in S. Helleri) is very short and 

 nodulouslj swollen ; nail setiform. Telson long and not 

 broad, breadth at base scarcely equal to half the lenotli, con- 

 siderably narrowing to the extremity; cleft of moderate 

 width, extending about one fourth of total length ; outer 

 margin with about sixteen spines, the four or five basal spines 

 separated by an interval from the following. Inner uropods 

 with numerous spines (20-22) arranged in sets, each set 

 commencing with a small spine, followed by others of gradu- 

 ally increasing length, the most distal spine at (but not on) 

 the extremity — a position most unusual ; otolith small. 

 Fourth j)Jeopods of male of the structure which usually prevails 

 in this group, but rather shorter than usual. Length 

 7 millim. 



Hah. Starcross, Devon, 1884 {Mr. C. Parker) ; Tarbert, 

 Loch Fyne, 1885 {3Ir. G. Brook) : Mus. Nor. 



Distribution. The types of the species were taken by Prof. 

 G. O. Sars at Goletta, in the Mediterranean. 



Characteristic features of this species are the nodulous 

 character of the first joint of the tarsus of the legs, by which 

 it may be distinguished from all species except iS. Helleri ^ 

 and from that species its smaller size, stouter build, and the 

 narrower telson, shorter antennal scale, and armature of 

 uropods distinguish it ; moreover in this species the outer 

 uropod is not more than one fifth longer than the inner, but 

 in S. Helleri it is at least one third longer. 



Genus 12. Mysis, Latreille. 



Very like in all respects to Schistomysis, but antemial scale 

 lanceolate (or subulate in M. mixta) , four and a half to nine 

 times as long as broad, ciliated all round ; apex narrowly 

 rounded (or spiniform in M. mixta). Fourth j^l&opod of 

 male similar in jointing and general structure to those of 

 Schistomysisj and in J/, mixta in all ways conforming to that 

 genus ; but in other species (J/, oculata and M. relicta) the 

 outer branch is much shorter, not more than two or three 

 times the length of inner branch, while the outer flagellum is 

 reduced to a spine-like process and the inner has the first 

 articulation much thickened, so as to almost resemble the 

 joint from which it springs, and the second articulation is 

 reduced to a spine-like process. 



M. ocidata, Fabr., must be regarded as the type of the 

 genus Mysis. 



