5i 



The antennae, mandibles, maxillae, and first maxillipedes are nearly similar to those of 

 Gaetanus /a/i frons. 



The lamella on the basal joint of the second maxilliped, appears to be similar to that 

 of Gaetanus latifrons, but the preparation was slightly damaged during dissection, and the apex 

 of the lamella was destroyed. 



'I he exopodite of the first pair of feet is incompletely three-jointed. The division across 

 the middle of the first joint, although fairly well defined, does not appear to pass right through. 



The inner margin of the first joint of the basiopodite of the fourth pair of feet, is 

 turnished with seven short spines. 



The fifth pair of feet is absent. 



Two specimens were obtained from the plankton collected with the Hensen vertical net 

 at Station 276 (750 metres to surface). 



It is only with some hesitation that I describe the above species as new. Both specimens 

 .although well developed are not quite mature. The narrowly rounded last thoracic segment 

 with its short, stout and almost upright spines when seen in lateral view, may help to identify 

 it when mixed up with other species of Gae/anus. 



Genus Gaidius Giesbrecht, 1895. 



This genus is distinguished from the other members of the family by the short one- 

 pointed rostrum. The exopodite of the first pair of feet in the female is composed of two joints. 

 The inner margin of the first joint of the basiopodite of the fourth pair of feet is without 

 armature. The male has a well developed prehensile fifth pair of feet. The exopodite of the 

 first pair of feet appears to be indistinctly three-jointed in some specimens. 



Two species were obtained from the 'Siboga' material. 



1. Gaidiics simi/is (T. Scott). Plate VII, figs. 1 — 11. 



Eucliaeta hessei var. similis T. Scott, 1893 (male only), p. 58, pi. VI, figs. 24, 25. 



Gaidius pungens Giesbrecht, 1895, p. 249, pi. 1, figs. 1 — 4. 



Gaidius pungens Giesbrecht & Schmeil, 1898, p. 32. 



Eucliaeta simi/is Giesbrecht & Schmeil, 1898, p. 52. 



Cliiridius tenuispinus Sars, 1900, p. 6j, pi. XVIII. 



Cliiridius tenuispinus Sars, 1902, p. 30, pi. XVIII. 



Gaidius tenuispinus Sars, 1903, p. 162, pi. VI (suppl.), fig. 1. 



Gaidius pungens I. C. Thompson, 1903, p. 17. 



Eucliaeta hessei var. similis, I. C. Thompson, 1903, p. iS. 



Gaidius pungens Wolfenden, 1904, p. 112, pi. IX, fig. 43. 



Gaidius pungens Esterly, 1905, p. 146, fig. 15. 



Gaidius tenuispinus Farran, 1905, p. 33. 



Gaidius tenuispinus Pearson, 1906, p. 13. 



Gaidius pungens Pearson, 1906, p. 12. 



Gaidius tenuispinus Farran, 1908, p. 32. 



Gaidius tenuispinus van Breemen, 1908, p. $6, fig. 39. 



Gaidiits simi/is appeared to be rather rare in the plankton collected during the traverse 

 of the 'Siboga', and was only obtained at the following stations. 



5 1 



