NOTODELPHYS. 131 



than twice as long as the preceding segment, and the 

 lateral seta is placed on the middle of the external 

 margin (fig. 9). Both branches of the fifth pair of 

 feet (fig. 10) are very much smaller than in either 

 of the foregoing species and much more slenderly 

 spined. Length of female fVth ^th of an inch 

 (2 3 mm.), of male y^-th of an inch (3 mm.). 



N. agilis has occurred in Ascidians taken off the 

 coasts of Durham and Yorkshire, in depths of from 

 twenty to thirty fathoms, and among specimens from 

 the branchial sac of Ascidia sordida, Shetland, sent to 

 me by the Rev. A. M. Norman. 



4. NOTOPELPHYS PEASINA, Thorell. PI. XXX, figs. 



1115. 



Notodelphys prasnia, Thorell. Loc. cit., p. 41, tab. v, fig. 7 (1859). 



The caudal segments (fig. 15) are in this species 

 much shorter and stouter than in any other, their 

 length being not more than equal to the breadth. 

 The two principal tail seta?, more especially the inner 

 one, are very broad. The branches of the fifth pair 

 of feet (fig. 14) are very small, the outer about thrice 

 as long as broad, the inner about as broad as long. 

 Length of female yVth of an inch (2'3 mm.). 



This species was more abundant than any other in 

 a collection of Entomostraca taken from the branchial 

 sacs of Ascidia mentula at Oban by the Rev. A. M. 

 Norman, to whom I am much indebted for the 



