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I prefer to regard the 'Siboga' specimens as distinct. The appendicular seta and the second 

 inner seta on the furcal joints are of about equal length. They are longer than any of the others. 

 Occurrence. Five specimens were obtained from the plankton collected with the 



Hexsen vertical net at the followincr stations. 



o 



Stat. 230 (2000 metres to surface), 2 specimens. — Stat. 243 (1000 metres to surface), 2 

 specimens. — Stat. 276 (750 metres to surface), t specimen. 



Genus Valdiviella Steuer, 1904. 



This genus was established by Steuer in 1 904 for a Calanoid closely related to Euchaeta, 

 but easily recognised by its bifurcate rostrum. The incomplete jointing of the exopodites of the 

 first and second pairs of feet, and the indistinctly three-jointed endopodites of the third and 

 fourth pairs of feet are also characters of this genus. 



Two species belonging to this genus were found in the plankton collected by the 'Siboo-a' 

 in the Malay Archipelago. 



1. Valdiviella gigas (Brady). Plate XXII, figs. 17 — 26. 

 Euchaeta gigas Brady, 1883, p. 65, pi. XXII, figs. 1 — 5. 



One specimen of a form apparently identical with the species described by Brady in 

 the report on the 'Challenger' Copepoda as Euchaeta gigas, was found in the plankton collected 

 with the Hensen vertical net at Station 230, 2000 metres to the surface. 



The rostrum is distinctly bifurcate. The fourth and fifth thoracic segments are completely 

 separated. The last thoracic segment is produced posteriorly into small points. The specimen 

 was immature and possessed a fifth pair of feet similar to that shewn by Brady. 



The antennules are twenty-three-jointed, and a number of the joints are furnished with 

 sensory organs. 



The antennae, mandibles, maxillae and maxillipedes are of the normal female Paraeuckacia 

 type. The mandible is well developed and is provided with cutting teeth. 



The exopodite of the first pair of feet is composed of two joints. The middle of the 

 outer margin of the first joint is furnished with a strong spine. 



The exopodite of the second pair of feet is very indistinctly three-jointed. The division 

 between the first and second joint is only marked by an overlapping at the base of the outer- 

 edge spine, and by a seta on the inner margin. The endopodite is one-jointed. 



The exopodites of the third and fourth pairs of feet are indistinctly three-jointed. The 

 endopodites are tvvo-jointed. 



The fifth pair of feet is almost symmetrical but is very rudimentary. Each foot consists 

 of a two-jointed basiopodite, a moderately long unjointed exopodite, and a small endopodite. 



The abdomen is composed of four segments. The genital segment is shorter than any 

 of the others. 



Length 8 mm. The size of the form described in the report on the 'Challenger' Copepoda 



is given as 5,25 mm. 



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