Kev. Canon A. M. Norman on British Mysitla3. 2-37 



length ; distally furnished witli a circlet of very long plumose 

 sette, which reach nearly half the length of the very sliort inner 

 iihanient, which in the described specimens has only tiiirteen 

 articulations. Antennal scale ovate, broad, witii broad, well- 

 rounded extremity ; breadth two fifths of length ; outer 

 margin naked, terminating in a large spine which is just on 

 a level with the extremity of peduncle of antennae ; extremity 

 reaching far beyond that spine ; the second joint bearing six 

 seta3. Legs having tarsus composed of four or five articu- 

 lations. Telson cleft at the apex to rather more than one 

 fourth of the length, serrations of cleft unusually few and 

 large (about 40) ; lateral margin with 15-17 spines. Inner 

 uropods remarkably twisted and bent ; inner margin with 

 about 15 spines on its central portion, of which the more 

 distal are of great size and equal in length to the breadth of 

 the uropod at that part; beyond this the uropod is very- 

 narrow, and just before the extremity there is a single very 

 large spine. Outer uropod'i much longer than inner, unusually 

 parallel-sided ; extremity widely truncate, eight seta3 taking 

 their origin from this blunt extremity. Length 10 millim. 



The male has the sexual lobe of the antennules of great 

 size and linguiform, the extremity arching backwards and 

 inwards ; inner filament longer than in female, outer directed 

 at nearly a right angle outwards. Penis not twice as long as 

 broad. 



IJah. Starcross, Devon {Mr. G. Parker, 1884) : Miis. Nor. 



This species is distinguished at once from all others by the 

 character of the uropods, especially the inner. There is a 

 slight tendency to a twist in the same organ in S. spiriius, 

 but to nothing like the extent to which it is carried in the 

 present species, while the spination of the inner margin is 

 quite different from that and from all other forms. 



4. Schistomysis Ilelleri (G. O. Sars). 



187G. My sis Helleri, G, O. Sars, Nye Bidratr til Kundskabcn om 

 Middelhavets Littoralfauna, I. Middelliavets Mysider, p. 8, pis. i. aud 

 ii. 



18^3. Austrom;/sis Helleri, Czerniavsky, /. c. fasc. iii. p. G7. 



1885. Mysis Helleri, Cams, /. c. p. 2GG. 



General form short and robust ; width of cephalotliorax in 

 front subequal to that of first segments of pleon ; adorned 

 with branching pigment-cells. Eyes short, somewhat pyri- 

 form ; the cornea reaching a little beyond the sides of the 

 cephalothorax. Antennules having the peduncles moderately 

 long and moderately robust ; the flagella long, the external 

 longer than the cephalothorax. Antennal scale rhoniboidal, 



