146 COPEPODA. 



STENHELIA VARTANS, Norman & T. Scott. (Pis. X. fig. 5 ; 

 XIV. fig. 13 ; XV. figs. 4, 14 ; XVI. fig. 3 ; XVII. fig. 2.) 



1905. Stenhelia various, Norman & Scott, Ann. & Mag. Nat. Hist, 

 ser. 7, vol. xv. p. 287. 



Description of the female. This Stenhelia closely resembles 

 S. neglecta just described, both as to its size and the structure 

 of its appendages, and might easily be confounded with it ; 

 but a critical examination reveals certain differences, of 

 which the following are the more important. 



The antennules are elongated as in S. nec/lecta, and are 

 composed of eight joints ; the entire length of the first four 

 joints is scarcely three times the entire length of the last 

 four ; the second joint, which is the longest, is more than 

 double the length of the third joint, but in S. neglecta the 

 length of the second joint is to that of the third as four is to 

 three. The fourth joint of the species under consideration 

 is about one and a half times as long as the third one ; 

 the fifth, sixth, and seventh joints are subequal and very 

 small, while the end joint is about equ:d to the combined 

 lengths of the sixth and seventh (PI. XV. fig. 4). The 

 formula shows approximately the proportional lengths of the 

 various joints : 



Proportional lengths of the joints . . 8.17.8.12.3.4.4.7 

 Numbers of the joints I 2 3 45678 



The secondary joints of the antennas are three-jointed, but 

 the middle one is small (PI. X. fig. 5). 



The mandibles and other appendages of the cephalon and 

 also the first pair of thoracic feet are similar to those of 

 Stenhelia neglecta. 



The fifth pair also resemble those of that species, but 

 differ somewhat in the form and armature of both the primary 

 and secondary joints. The primary joints terminate in a 

 narrow apex ; there are three short and subequal setae on the 

 inner margin and two slender terminal seta? of unequal 

 length; the space w r hich separates the two terminal sete from 

 the other three is distinctly greater than that which separates 

 these three from one another. The secondary joints are 

 subovate in outline, and nearly twice as long as broad, the 

 outside edge is nearly straight, but the inner is distinctly 

 rounded ; a seta springs from near the middle of the outer 

 margin and four from the angularly rounded extremity of 

 the joint as shown by the drawing (PL XVII. fig. 2). 



No males of this form have been observed. 



Habitat. Fowey, Cornwall, outside the harbour, collected 

 May 12th. 1003 ; apparently not common. 



