2Ó2 



i. Pachysoma punctatum Claus. 



Pachysoma pandata Claus, 1863, p. 163, pi. XXV. 



Pachysoma punctatum Brady, 1883, p. 121. 



Pachysoma punctatum Giesbrecht, 1893, p. 612, pis. 4 & 48. 



Pachysoma punctatum T. Scott, 1893, p. 119, pi. XIII, figs. 18 — 24. 



Specimens identical with the above species were found in the plankton collected at the 

 following four stations. 



Stat. 142, 1 specimen. — Stat. 143 (HENSEN vertical net, 1000 metres to surface), 3 speci- 

 mens. - - Stat. 144, 1 specimen. — Stat. 185 (HENSEN vertical net, 1536 metres to sur- 

 face), 1 specimen. 



Pachysoma punctatum can readily be separated from Pachysoma tuberosum Giesbrecht, 

 by the second and third abdominal segments being of nearly equal length. The second segment 

 of the abdomen of Pachysoma tuberosum is distinctly shorter than the third segment. 



This species has hitherto only been known from the Atlantic Ocean, and from the 

 Mediterranean. 



Genus Hermannella Canu, 1891. 



The members of this genus can be recognised by the stylet-shaped form of the rnandible 

 and of the fïrst pair of maxilipedes, and by the exopodites and endopodites of the first four 

 pairs of feet being three-jointed. 



The three-jointed exopodite and endopodite of the fourth pair of feet is the principal 

 char-acter that distinguishes this genus from Lichomolgus and Pscudanthcssius. 



One species, apparently undescribed, was represented in the plankton collected by the 

 'Siboga' in the Malay Archipelago. 



1. Hermannella concinna nov. sp. Plate LXVIII, figs. 1 — 10. 



Female — length 2,9 mm. 



Seen from above, the body appears nearly circular in outline. The frontal margin is 

 broadly rounded. The fifth thoracic segment is comparatively large and is sub-quadrangular in 

 shape, with the anterior and posterior ends considerably contracted. 



The abdomen is composed of four segments. The combined length of the abdomen 

 and furcal joints is contained nearly twice in the total length of the cepkalothorax, from the 

 frontal margin to the distal end of the fifth thoracic segment. The genital segment is rather 

 large and is moderately expanded in the middle. It is as long as the combined length of the 

 second and third segments added to half of the length of the anal segment. The second and 

 fourth segments are sub-equal in length. The third segment is much smaller than the others. 

 The furcal joints are cylindrical and of moderate length. The joints are slightly longer than 

 the anal segment and are furnished with one outer marginal seta, and four apical setae 

 (Plate LXVIII, fig. 1). 



The antennules are slender and seven-jointed. The second and fourth joints are long. 



262 



