NOTOPTEROPHORUS. 141 



caudal rami abruptly flexed upon the abdomen, bear- 

 ing two strong curved spines and a few setae (fig. 13). 

 Anterior antennae short, bent at a right angle in the 

 middle (fig. 3) ; distal half densely setiferous ; poste- 

 rior antennae (fig. 4) stout. The inner branches 

 of the swimming feet are short (figs. 10, 11) and 

 destitute of marginal spines, but bear three or four 

 slender terminal setae ; the marginal spines of the 

 outer branches (fig. 11, a) are surrounded with a 

 delicate ciliated lamina. Fifth pair (fig. 12) 1 -jointed, 

 with three apical cilia, two long and one short. 

 Length yV^ n f an i nc ^ (1*4 mm.). 



In the branchial sac and water-passages of Ascidia 

 mentula, Shetland and Oban (Rev. A. M. Norman). 



Genus 4. NOTOPTEROPHORUS, Costa (1852). 



Body composed of ten segments and provided with 

 several dorsal wing-like expansions ; anterior antennae 

 10- (8-, Hesse) jointed ; posterior 3-jointed, clawed at 

 the apex. Mandibles, maxillae, and foot-jaws, similar 

 to those of Doropygus. Inner branch of first pair of 

 feet 2-jointed ; the rest have both branches 3-jointed. 



Except for the peculiar wing-like dorsal appendages 

 there seems to be little to separate this genus from 

 Doropygus. Perhaps, indeed, we may look upon 

 these expansions as only an extreme development, 

 with modification, of the dorsal gibbosities of I). 

 auritus. 



K 



