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i. Rhynchothalestris rufocincta (Norman). Plate LXII, figs. 12 — 20. 



Thalestris rufocincta Norman, (Brady, 1S80, vol. II, p. 125, pi. LVI, figs. 1 — 9). 



Thalcstris rufocincta I. C. Thompson, 1S96, p. 25. 



Thalestris rufocincta T. Scott, iqoi(a), p. 354. 



Thalcstris rufocincta Pearson, 1905, p. 13. 



Rhynchothalestris rufocincta Sars, 1905, p. 120, pis. LXXIII & LXXIV. 



Rhynchothalestris rufocincta T. Scott, i9o6(«), p. 315. 



Rhynchothalestris rufocincta Norman & T. Scott, 1906, p. 168. 



Males and females that are perfectly identical with the above species were found in the 

 plankton, and in the washings from dredged invertebrata collected at the following stations. 



Stat. 35, surface, 1 female. — Stat. 40, surface, Pulu Kawassang, Paternoster Islands, 1 female. - 

 Stat. 164, bottom, 32 metres, 2 females and 2 males. -- Stat. 273, bottom, 13 metres, 

 1 female and 1 male. 



The female can readily be recognised by the shape and armature of the fifth pair of 

 feet. The last joint of the endopodite of the second and third pairs of feet of the male is 

 peculiarly modified. The illustrations of the last joint of these feet of the 'Siboga' males (Plate 

 LXII, figs. iS and 19), are identical with the figures given by Sars in 'Crustacea of Norway' 

 Vol. V. The upper distal angle of the fifth last joint of the male antennules is produced into 

 a well defined tooth (Plate LXII, fig. 17). Length of 'Siboga' specimens - - female .98 mm., 

 male .7 mm. 



Rhynchothalestris rufocincta has been recorded from the coasts of Britain, France, and 

 Norway. 



2. Rhynchothalestris sim i/is nov. sp. Plate LXII, figs. 6 — ri. 



Female — length 1,47 mm. 



This species bears a very close resemblance to Rhynchothalestris rufocincta, but it can 

 be separated from it by the following characters. The proportional length of the joints of the 

 antennules is different. The seventh and eighth joints are of nearly equal length. In Rhyn- 

 chothalestris rufocincta the eighth joint is distinctly smaller than the seventh joint. The second 

 joint of the second pair of maxillipedes is moderately large and comparatively narrovv. The 

 terminal claw exceeds the length of the second joint. The inner expansion of the proximal 

 joint of the fifth pair of feet is very broad and its apex is rather truncate. The marginal setae 

 are placed fairly close together round the apex. The distal joint is proportionally narrower than 

 the distal joint of Rhynchothalestris rufocincta (Plate LXII, fig. 10). The furcal joints are one 

 and a half times longer than broad. 



Occurrence. — One female was found in the washings from dredged invertebrata 

 collected at Station 273, from a depth of 13 metres. 



Genus Idomene Philippi, 1843. 



The members of this genus can be recognised by the very depressed body, by the 



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