COPEPODA 



187 



tively long antennulae and comparatively short Se 2 there is reason to suggest that the value of these 

 characters ought not to be exaggerated. 



57. Euchaete acuta Giesbrecht. 

 (PI. VI figs 12 a c; text-figs 56 a b.) 



1892. Euchaete acuta n. sp. Giesbrecht, p. 246, Taf. 16 and 37. 



1898. Giesbr. Giesbrecht & Schmeil, p. 38. 

 1903. J. C. Thompson, p. 18. 



1903. J. C. Thompson & A. Scott, p. 244. 



1904. Wolfenden, p. in. 



1904. Cleve, p. 190. 



1905. G. O. Sars, p. 4. 

 1905. Farran, p. 35. 



1905. Euchaete acuta Giesbr. Esterly, p. 157 fig. 23. 



1906. 

 1908. 

 1908. 

 1909. 

 1909. 

 1911. 

 1912. 



Pearson, p. 17. 



Farrau, p. 40. 



v. Bremen, p. 51, fig. 56. 



A. Scott, p. 65, pi. XX figs i - 9. 



Pesta, p. 23. 



Wolfenden, p. 299. 



Pesta, p. 22. 



Text-fig. 56. Euch/xte acuta 



Giesbr. Yd 1 (St. V). 



a. Abdomen X 18. b. Pes V 



in anterior view X 33- 



Description. f.. Size: 4-02 ram.; anterior division (17 -|- 0-97) = 2-67 mm.; urosome 1-35 mm. 

 Giesbrecht's specimen measured 4-1 mm., Farran's 4-4 mm. and Scott's 4-2 mm. 



The genital area has on each side of the vulva a lamina-shaped process, somewhat larger on 

 the right side; the outline is, as shown in fig. i2a, somewhat different from Giesbrecht's fig. 47 (Taf. 37). 

 S c o t t's fig. 4 of the abdomen in dorsal view differs distinctly by the presence 

 of a right lateral process (may possibly be the process on the right side of the 

 vulva, which is visible when the animal is not examined in complete dorsal 

 view). The subapical seta is much longer than the St. 2. 



The antennulae, mouth-limbs and natatory limbs are scarcely different 

 from Giesbrecht's description. 



The epistoma and the anterior surface of the labrum do not show any 

 features of interest. The hairs on the oral surface of the labrum show a rather 

 simple arrangement. The group i is, as usual, placed somewhat laterally, but 

 is not distinctly separated from the group 2; the groups 34 are small and well 

 marked out ; the group 5 is fairly big. The transverse row behind the median spot Nr. 3 is short and 

 narrow. No lateral group was observed (cf. fig. 12 b). The lateral group in front of the lamina labialis 

 (fig. 12 c) consists of small granules, and is well separated from the median groups; these consist, as 

 shown in fig., of fairly long hairs; the inner group of granules anteriorly was not observed. 



Yd' (St. V). Size: 372mm.; anterior division 2 - 68 mm. ; urosome 1-04 mm. 



The lateral corners are rounded. The subapical setae are, as in the adult females, stronger as 

 well as much longer than the St. 2. The antennulae extend scarcely to the end of the anterior division. 

 The appendages are scarcely different. The structure of the fifth foot is seen in text-figs 56 a b. 



Occurrence. The species was not gathered by the Ingolf Exp. ; but, as it was found by the Thor 

 at the following 3 stations, I have included it here. 



'5/ 6 1905 St. 82 5i32 L,. N. n43 L. W. Yt. 1200 M. Wire i f ?. 



2 % 1905 St. 88 48=09 L. N. 83<D L. W. Yt. 300 M. Wire 15 f ? + i yd 1 . 



2I /6 1905 St. 90 4747 L,. N. 8ooL. W. Yt. 300 M. Wire if?. 



24* 



