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and the true position of the genus in the classification wil! probably remain uncertain until the 

 male is discovered. 



The rostrum is entirely absent. The first pair of maxillipedes is peculiarly modified, and 

 is furnished with powerful claw-like spines. The exopodite and endopodite of the first pair of 

 feet is composed of a single joint. The exopodites of the second, third and fourth pairs of feet 

 are three-jointed. The endopodite of the second pair of feet is one-jointed. The endopodites 

 of the third and fourth pairs of feet are three-jointed. The fifth pair of feet is absent. 



One species belonging to this remarkable genus, was represented in the plankton col- 

 lected by the 'Siboga', during the investigations in the Malay Archipelago. 



i. Chiridiclla macrodactyla Sars Plate XXXVI, figs. 9 — 21. 



Chiridietta macrodactyla Sars, 1907 (<rz), p. 8. 



Chiridiclla macrodactyla Farran, 1908, p. 46, pi. IV, figs. 6 — 14. 



A single specimen agreeing very well with Sars' preliminary description of the above 

 species and with the figures given by Farran, was obtained from the plankton collected with 

 the Hensen vertical net at Station 148, 1000 metres to the surface. 



The specimen measured 2,73 millimetres in length. I see 110 other difference between 

 the ■Siboga' form and Sars' description, than that the combined length of the abdomen and 

 furca is very slightly less than one-third of the total length of the cep halothorax, from the 

 frontal margin to the base of the genital segment. 



The specimens from the deep water off the West Coast of Ireland appear to be almost 

 identical with the 'Siboga' form. The figure of the first maxilliped is the same as that given 

 in this report. Farran points out some minor differences between his specimens, and the des- 

 cription given by Sars. Similar differences are also apparent between the figures given in the 

 present report and those shewn by Farran. 



7. Family Phaennidae. 

 Genus Phaenna Claus, 1863. 



The only known member of this genus is distinguished from the other genera that are 

 included in the family Phaennidae, by the entire absence of a fifth pair of feet in the female, 

 by the form of the organs on the apex of the first pair of maxillipedes in both sexes, and 

 by the structure of the fifth pair of feet of the male. 



The apex of the first maxilliped is furnished with a strong claw-like spine, and a number 

 of short cylindrical appendages which terminate in a brush of fine cilia. The fifth pair of feet 

 is represented in the male by the exopodites only. 



One species is known. A few specimens of it were found in the plankton collected by 



the 'Siboga'. 



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