The bifurcate rostrum and the incomplete segmentation of the swimming feet, indicate 

 that the 'Siboga' specimen belongs to the genus Valdiviella. The specimen was evidently a 

 female, and no doubt the rudimentary fifth pair of feet would disappear at the final ecdysis. 



2. Valdiviella ? brevicornis Sars. Plate XXII, fig. 27 — 35. 

 Valdiviella brevicornis Sars, 1905 (a), p. 17. 



A single male specimen belonging to the genus Valdiviella, and doubtfully included 

 under Sars' species Valdiviella brevicornis, was obtained from the plankton collected with the 

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



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

 completely fused. The posterior margins of the last thoracic segment are narrowly rounded. 



The antennules are twenty-three-jointed and are well furnished with sensory organs. 



The antennae, mandibles, maxillae and maxillipedes are of the normal male Paraeucliaela 

 type. The mandibles have no toothed biting edge. The maxillae and maxillipedes are much reduced. 



The exopodite of the first pair of feet is distinctly three-jointed. Each joint is furnished 

 with an outer-edge spine. 



The exopodites and endopodites of the second, third and fourth pairs of swimming feet 

 are similar to those of Valdiviella ?io-as. 



The fifth pair of feet is well developed and prehensile. The basiopodite is two-jointed. 

 The second joint of the right basiopodite is much inflated at its proximal end. The distal 

 portion of the joint is long and narrow. The joints of the basiopodite of the left foot are 

 moderately long and cylindrical. The exopodite of the right foot is apparently only one-jointed. 

 The joint is moderately long and has a lamelliform apex. The exopodite of the left foot is 

 composed of three, short, subequal joints. The last joint is spiniform. The endopodites are 

 one-jointed. The right endopodite is long and slender with a distinctly inflated apex. The right 

 endopodite is very short and is somewhat club-shaped. 



The abdomen is composed of five segments. The first, second, third and fourth segments 

 are all of about equal length. The fifth segment is very small. 



Length — 5 mm. 



The specimen is clearly a Valdiviella by its bifurcate rostrum and by the incomplete 

 segmentation of the second, third and fourth pairs of feet. It is not unusual to find the exopodite 

 of the first pair of feet of the males of some of the Calanoids to be slightly different in the 

 jointing from the females. From its size, the specimen may be the male of Sars' Valdiviella 

 brevicornis, but as no figures of Sars' species have yet been published its relationship must 

 be regarded as doubtful. The specimen is proportionally much smaller than either Valdiviella 

 oligarthra Steuer, or Valdiviella insignis Farran. 



Genus Chiridiella Sars, 1907 (a). 



This genus was established by G. O. Sars in 1907 for an aberrant Calanoid form, 

 which Farran suggests may lead a semi-parasitic mode of existence. Only the female is known T 



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