COPEPODA 



167 



The genital somite is, as seen in fig. 46 a, distinctly produced below, but the outline is not quite 

 like any of the published drawings. The structure of the vulva seems to be a good deal more com- 

 plicated than figured by Wolfenden. The subapical seta is more slender, but longer than St. 2. 



The antennulae are like Scott's fig. 11; the segments 24^25 are distinctly shorter than seg- 

 ment 19, and 23 than 16. The mouth-appendages are scarcely different from those of E. norvegica. 



The pes I is in main features like E. n., but distinctly different from Scott's fig. 13; the arti- 

 cular membrane between Re I — II is fairly developed anteriorly, but posteriorly is wanting, except 

 medially; the Se Re I is fairly developed. The pes II is like Wolfenden's fig. 50 c, but in details 

 is different from Scott's figure; the Se Re II scarcely reaches the base of Se 1 Re III, and Se 2 al- 

 most reaches the base of short Se 3. On the posterior surface of the second basipodite in the fourth 

 pair of legs a number of delicate hairs are found in the middle. 



The epistoma and outer surface of the labrum are in the main like those of Euch. glacialis (cf. p. 169) 

 and slightly different from E. norv. The oral surface of the a 



labrtmi is like E. norv., except the two first groups of 

 hairs, which are placed as shown in fig. 4 a. The area 

 in front of the lamina labialis is like that of E. norv., 

 but inwards delicate spines are found instead of granules; 

 the most lateral group of hairs is almost as wide as long. 

 The lobus labialis possesses in similarity with Euc. glacialis 

 a posterior lateral group of hairs. 



o*. Size: 5-89 mm.; anterior division (2"56 -J- i - 6); 

 urosome 173. 



Shape of the body is scarcely different from E. 

 norv. The rostrum is a little more obtuse and somewhat 

 shorter. The lateral corners are rounded and somewhat 

 less produced, but more produced on the left than on 

 the right side; the difference is, however, less marked 

 than in E. norv. (text-fig. 46 c). c 



_., , 7 , 1,1 i,i 1 Text-fig. 46. Euchate tonsa Giesbr. 



The antennulae reach somewhat beyond the end a f? Genkal somite x i6 b f?> uteral corner 

 of the thorax and are scarcely different from those of from the right x 16 and x 52. c. fd 1 . Lateral corner 



from the right X 18. d. Pes V Ri sin. from the right 

 E. norv. ( j n s i tu ) x 59 . e Yo*l?) (St. V) with abnormal pes V 



The pes I has a well developed articular mem- X 16. f. Yc?(?) (St. V). Abnormal pes v x 39- g- yc? 



(St. V). Pes V in anterior view X 33- 



braue between Re I — II, and the Se Re I is very short, 



scarcely three times as long as wide. The pes II differs from $ by the slightly different shape of the 

 Se Re II— III, and by the Se 2, which does not reach the base of Se 3 ; the base of the process, pos- 

 sessing the Se 2 Re III, is, in E. norv., placed almost as near the end as the base, but is here placed 

 distinctly nearer the base than the tip. 



The fifth pair of legs differs from that of Euc. norv. by the different shape and serration of 

 the process of Re II sin, which is distinctly longer, not shorter, than the ringed appendage (fig. 4 b), 

 and by the slightly different shape of the left endopodite (text-fig. 46 d). 



