52 



Stat. 66, i specimen. — Stat. 141, 2 specimens. ■ — Stat. 142, 1 specimen. — Stat. 203 

 (Hensen vertical net), 1 specimen. — Stat. 245, 1 specimen. ■ — Stat. 252, 1 specimen. 



One female and six males were found. Female — length 3 mm. Male — length 2,87111111. 



The species described by my father from the Gulf of Guinea in 1893 as Euckacfa hessei 

 var. simi/is, appears to be undoubtedly the male of the form described by Giesbrecht in 1895 

 as Gaidius pungens, from females only. Gaidius pungens Giesbrecht, will therefore, necessarily, 

 o-ive way to Gaidius similis (T. Scott). The fifth pair of feet of the male figured in the 

 'Report on Entomostraca from the Gulf of Guinea', only differs from that shewn in the present 

 report, by the absence of the endopodite of the left foot. This no doubt, is due to the fact 

 that the endopodite lies close to the exopodite, and may easily become folded under it. I find 

 too, that the exopodite of the first pair of feet in some of the males may be very indistinctly 

 three-jointed, according to the state of maturity. 



I regard the form described by Sars as Gaidius (Chiridius) tcnuispinus, that lias been 

 recorded by Farran, Pearson, and van Breemen, from the North Atlantic, to be identical with 

 this species. 



The first joint of the exopodite of the right foot of the males from the 'Siboga' material, 

 lias a lamella-like process on the middle of the inner margin, which may be very easily overlooked. 



The species apparently has a wide distribution. 



2. Gaidius notacantlius Sars. Plate XXI, figs. 24 — 33. 



Gaidius notacantlius Sars, 1905 (a), p. 9. 



Gaidius notacantlius Farran, 1908, p. 33, pi. III, fig. 7. 



One specimen, a male, apparently belonging to this species was found in plankton 

 collected with the Hensen vertical net at Station 148, 1000 metres to surface. Length 5,9 mm. 



The fifth pair of feet agrees fairly well with the figure given by Farran, except that 

 the second joint of the right exopodite is shorter, but this may be due to accident or slight 

 immaturity. 



The records by Sars and Farran appear to be all that is known of the distribution of 

 this species. 



Genus Gaidiopsis nov. 



Forehead without cephalic spine, with short one-pointed rostrum. The fourth and fifth 

 thoracic segments are completely separated, and the fifth segment is produced into strong lateral 

 spines. The abdomen is composed of four joints. The antennules are twenty-four-jointed. The 

 antennae, mandibles, maxillae and maxillipedes, are almost similar to those of Gaidius. The 

 exopodite of the first pair of feet is distinctly three-jointed. The second, third and fourth pairs 

 of feet are similar to those of Gaidius. The endopodite of the second pair is distinctly two-jointed. 



This new genus resembles yEtidcoftsis, in the complete segmentation of the fourth and 

 iitth thoracic segments, and the distinctly three-jointed exopodite of the first pair of feet. It also 

 resembles Gaidius in the short one-pointed rostrum. 



Only one species was observed and the male is unknown. 



