COPEPODA 



I2 3 



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 (fig. 2 a) shows as seen in figures (cf. 3 c) some 

 similarity to that of E. curticauda, but the arrangement of the groups of hairs in the 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; the 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; the fourth 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/z/M group, which consists of about 40 rather slender setae, is partly fused with the 

 fourth; the sixth 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 lamina 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 34 spiuous 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 



. "if. 'Ill ~ x ,. - f , j. ~- ~~~ XN %J/ . _. i. ,_j 



series consists of two rather independent almost transverse v dext . r i,jges of Re III x 175. d e (in the 



rows; the third series seems onlv to be represented on the middle below ) ?<? < st v > Ri P 68 n ~ m X 57- 



f. yd 1 . Pes V ant. view X 57- 

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



row on the lobe a more medial and posterior portion; they?/?// 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. 



d 1 . Size of specimen from Thor St. 183 5*46 mm.; anterior division 4-37 mm.; urosome 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 Euch. 

 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 legs 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. 



16* 



b d e f 



Text- fig. 31. Euchirella messininsis Claus. 

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



