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and the true position of the genus in the classification will 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. 
1. Chiridiella macrodactyla Sars Plate XXXVI, figs. g—21. 
Chiridiella macrodactyla Sars, 1907 (a), p. 8. 
Chiridiella macrodactyla Farran, 1908, p. 46, pl. IV, figs. 60—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 no 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 cephalothorax, 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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