﻿COPEPODA 



123 



each side of the median concavity, of a medial transverse row of about 25 more spine-shaped setae. 



The chitinous system of the oral surface of the labrum (fisj. 2 a) shows as seen in figures (cf. 3 c) some 



similarit\- to that of E. ciirficauda, but the arrangement of the groups of hairs in tlie longitudinal 



series is distinctly different, and is indeed very characteristic. The first group consists of about 30 — 40 



setae, placed in a single inwards convex row; W\(t second group, which is perhaps fused with the lateral 



group, is represented by a big group of minute acicules; the third group consists of about 20 fairly 



long setae, and is converging towards the front; Wxq fourt/i group, consisting of about 25 fairly strong 



setae, has the anterior portion placed almost transversely, and is almost fused with corresponding part of 



the other side; the A'//// group, which consists of about 40 rather slender setae, is parth- fused with the 



fourth; the si.xth group is transverse, and consists of short delicate hairs. No transverse series of 



.spinules is observed behind the median circular spot Nr. 3, 



and the two series behind the fourth median .spot are fused 



to a square area, beset with spinules. 



The lautiua labialis, as seen in fig. 2 b, is smooth and 



very insignificant; the arrangement of setae in front of lamina 



is, as seen in fig. 2 c, somewhat different from that of E. cur- 



ticauda. Behind the lamina 3—4 spinous areas are observed 



on each side. The series of hairs behind and upon the labial 



lobes show a rather regular arrangement, as seen in fig. 2 c, 



the medial posterior groups of a few hairs could not naturally 



be referred to any of the series. The first series consists of a 



number of short hairs, placed in a rounded area; the second 



a— b (to the left), f 2. Ri pes II— III X 57. c Pes 

 series consists of two rather independent almost transverse y dext; ridges of Re III x 175. d— e (in the 



rows; the tinrd series seems onlv to be represented on the '""^<5'<= ''^'°"'' 5"^ <«'■ V) R' V^ H-III x 57- 



f. yn'. Pes V ant. view X t>'- 



labial lobes, and the fourtfi one has in addition to the regular 



row on the lobe a more medial and posterior portion; t\\(t fi/tfi group, which consists of somewhat 

 stronger setae, falls naturally into a median portion which is fused with the corresponding part of the 

 other side, and a lateral one which is continued to the end of the labial lobe. 



c?. Size of specimen from Thor St. 1.S3 5-46 mm.; anterior division 437 mm.; uro.some rog mm. 

 Giesbrecht's specimen measured 3-95 mm. 



The frontal keel is distinctly higher than figured by Giesbrecht (Taf. 36 fig. 25). The oral ap- 

 pendages are practically like Giesbrecht's description, but the mandibulae possess as in Euc/t. 

 rostrata a well developed manducatory portion; the labrum and labium show a similar development 

 as in this species. 



According to Giesbrecht (p. 240) the only difference between the natatory logs in males and 



females is found in the completely smooth inner margin of the fourth pair of legs in the males; in 



my specimens, however, the difference is even better marked than in E. rostrata and curticauda (PI. 



VIII fig. I). The articulation between Re I and II pes I is indicated, but the Se Re I is wanting; 



the Se Re II is quite rudimentary; the pore in the outer margin of Re II is well developed, but 



that of Re III seems to be wanting: The St. of the Re III pes II has about 50 instead of c. 25 teeth. 



i6* 



Text-fifir. ^i. Eucki'rella mcssimtisis Claus. 



