COPEPODA 



49 



1905. Eucalanus elongatus Dana. Esterly, p. 131 — 132, figs. 190S. Eucalanus elongatus Dana. v. Bremen, p. 15, fig. 10. 



6 a — d. 1908. — — — Farran, p. 21. 



1905. 



1905- 

 1906. 

 1906. 



Th. Scott, p. 222. 

 Farran, p. 30. 

 Pearson, pp. 6 — 7. 

 G. O. Sars, p. 2. 



1908, 

 1910. 

 1911. 



— Wolfendeu, p. 29. 



— Farran, pp. 93—94, pi. XIV. 



— Wolfenden, p. 204. 



Description, f?. Size: 6-5 mm. The females scarcely differ from Giesbrecht's description. 

 No glandular pores were observed in the natatory limbs. 



The labrnm proper, which is suddenly raised from the region lying in front of it, is by a 

 transverse groove divided into an anterior and a more raised posterior portion; the latter is divided 

 into three hairy lobes, a median and two lateral ones ' ■^ 



(text-fig. 9 a). The oral surface (fig. 5 a) shows a structure 

 similar to that found in Rhincalanus , but the two first 

 groups of the longitudinal series consist of fairly long and 

 slender bristles. In front of as well as behind the transverse 

 bar the skin is beset with a dense group of strong granules. 

 In front of the trebly divided lamina labiaUs (fig. 5 b) a 

 median longitudinal row of long and a lateral one of very 

 delicate setae are observed; in the middle a row of very 

 short hairs is found on each side, single behind and 

 double in front. Between the serrulae 6-dentatae a longi- 

 tudinal lateral series, a median group and more posteriorly a 

 transverse group of short setae are found ; behind the serrnla 

 an oblique group was seen. The area labialis possesses a 

 central group of hairs between the labial lobes, parti)' 



continued on the latter, which bear four fairly regular 

 rows of hairs. 



Text-fig. 9. EiicaLanns elongatus Dana. 



a. (to the left above) fj. Labrum etc. X 18. 



b. f?. Abdomen X iS. 



c. (to the right I fd". Labrum etc. X iS. 



d. fd'. Abdomen X 18. 



e. Y9 (St. V). Abdomen X iS. 



f. (to the right beneath). Yd" (St. V) X 18. 



fc?. Size: 4-5 — 5 mm. The fifth thoracic somite is better marked out, and the lateral corner is 

 less produced than in the female. The head is in front of the transverse groove more strongly convex 

 (text-fig. 9c) and the labrum is lower; its oral surface is smooth; the labial appendages are lower. 

 The intestine is well developed with the usual convexity and coecal sacs. 



The oral appendages are, as shown by Giesbrecht, greatly reduced. The legs of the fifth 

 pair (fig. 5 c) are more slender than figured by Giesbrecht; the left leg was, except in two spec- 

 imens, the longer. In a single male the terminal segments of the fifth pair possessed a small median 

 hair in addition to the terminal one. The fifth pair of the young male has the left leg a little longer 

 than the right; the Re is divided into two distinct segments, of which the latter bears two long 

 bristle^ (fig. 5 f, cf. Wolfenden PL IX, fig. 3); in a single young? male the number of setae in the 

 terminal segment was 3 instead of 2 (fig. 5 d) and in another young (?) male the structure was, as seen 

 in fig. 5 e, more like that of the mature male. 



J? (V). Size: 4-5 mm. The lateral corner of the last thoracic somite is like that of the fc?. 

 The urosome consists of three somites, as the two basal ones (text-fig. 9 e) are fused in most specimens 



The Ingolf-Expedition. III. 4. 7 



