92 ANNALS OF SCOTTISH NATURAL HISTORY 



joints large. Posterior antennae somewhat similar to those 

 of Longipedia, but the secondary branch is shorter, the width 

 of the joints being greater than the length. Mouth organs 

 similar to those of Longipedia. Both branches of each of 

 the first four pairs of swimming-feet of about equal length, 

 and, with the exception of the second pair, somewhat like 

 those of Longipedia ; the first joint of the inner branches of 

 the second pair very short, and armed with a stout conical 

 spine about equal in length to the second joint (Fig. 2). 

 Fifth, in both sexes rudimentary, consisting of a small basal 

 joint, bearing in the female four setae, one of which is rather 

 longer than the others, and densely plumose (Fig. 3). The 

 first and fourth segments of the abdomen without spinous 

 armature. Caudal stylets about equal in length to the two 

 last abdominal segments, and considerably divergent. The 

 animal is more slender than Longipedia coronata, and the 

 postero-lateral angles of the cephalo-thoracic and abdominal 

 segments are rounded (Fig. 1). Ovisacs two, large. 



One of the most conspicuous differences between Canuella 

 and Longipedia is in the structure of the second pair of swim- 

 ming feet. In Longipedia the inner branches of the second 

 pair are greatly elongated in both sexes, and form one of the 

 distinctive characters of the genus, the name of which has also 

 reference to this character. In Canuella, on the other hand, 

 both branches are of about equal length in both male and 

 female, and the fifth feet are rudimentary. Therefore, not- 

 withstanding the number of important points in which the 

 two forms agree, the differences described clearly separate the 

 one from the other ; and, moreover, while Longipedia has only 

 one, Canuella has two ovisacs. 



Canuella perplexa, sp. n. (provisional name) Plate II. 

 Figs. 1-3. 



1880. Longipedia coronata, Brady (fern.), "Brit. Copep." 

 vol. ii. p. 6, Plate XXXIV. Figs. 3, 9 ; Plate XXXV. Figs. 



!> 3>9- 



The characters of the genus are applicable to the species, 

 and therefore need not be repeated, this species being the 

 only one known. Length, 1 '4 mm. (y^th of an inch). 



Additional Notes. — {a) Males and females of a small (?) 



