I 2 I 



Females apparently iclentical with the above species, were obtained from the plankton 

 collected with the Hensen vertical net at the following stations. 



Stat. [l8 (yoo metres to surface), 3 specimens. — Stat. 141 (1500 metres to surface), 4 spe- 

 cimens. — Stat. 143 (1000 metres to surface), 4 specimens. — Stat. 185 (1536 metres to 

 surface), 3 specimens. — Stat. 203 (1500 metres to surface), 4 specimens. — Stat. 276 

 (750 metres to surface), 4 specimens. 



The genital segment of the 'Siboga' specimens, is equal to the combined length of the 

 second and third abdominal segments. The fifth pair of feet is composed of two free joints 

 attached to a basal part. The apical joint of one foot is furnished with two setae, and the 

 other with one only. (Plate XXXVII, fig. 11). Length 1,9 mm. 



The female fifth pair of feet of Metridia curticauda, a species closely related to Metridia 

 brevicauda^ has three free joints and a basal part. 



Metridia brevicauda has been recorded from the Atlantic and Pacific Oceans. 



3. Metridia macrura G. O. Sars. Plate XXXVIII, figs. 8 — 11. 

 Metridia macrura Sars, 1905 (^), p. 7. 



A single female agreeing with the preliminary description of the above species, was 

 found in the plankton collected with the Hensen vertical net at Station 230, 2000 metres to 

 the surface. Length 10,5 mm. 



The furcal joints are nearly three times the length of the anal segment. The joints are 

 twelve times longer than broad. The fifth pair of feet is very similar to that of the female of 

 Metridia princeps. 



4. Metridia princeps Giesbrecht. Plate XXXVIII, figs. 1 — 7. 



Metridia princeps Giesbrecht, 1889, p. 24. 



Metridia princeps Giesbrecht, 1893, p 340, pi. 33. 



Metridia princeps Giesbrecht & Schmeil, 1898, p. 107. 



Metridia princeps I. C. Thompson, 1903, p. 24, pi. VI, figs. 3 & 4. 



Metridia princeps Cleve, 1904, p. 192. 



Metridia princeps Sars, 1905 (£), p. 2. 



Metridia princeps Farran, 1905, p. 43. 



Metridia princeps Pearson, 1906, p. 24. 



Metridia princeps Esterly, 1906, p. 69, pis. 11, 13 & 14. 



Metridia princeps Farran, 1908, p. 61. 



Metridia princeps van Breemen, 1908, p. 1 10, fig. 127. 



Nine females and six males were obtained from the plankton collected chiefly with the 



Hensen vertical net at the following stations. 



Stat. 118 (900 metres to surface). • Stat. 128 (700 metres to surface). — Stat. 141 (1500 

 metres to surface). — Stat. 148 (1000 metres to surface). — Stat. 185 (1536 metres to 

 surface). — Stat. 203 (1500 metres to surface). — Stat. 217 (horizontal cylinder). — Stat. 

 243 (IOOO metres to surface). 



The furcal joints of both sexes are twice as long as the anal segment, and five times 

 longer than broad. Length, female 7,9 — 8,8, male 8,3 mm. 



121 



SlBOGA-EXl'EUITIE XXIX<7. 



16 



