1 67 



The abdomen is moderately long. It is composed of three segments. The combined 

 length ot the abdomen and furca is contained two and one-third times in the total length of 

 the cephalothorax, from the frontal margin to the base of the genital segment. The oenital 

 segment is symmetrical. It is as long as the combined length of the next two segments. The 

 dorso-lateral surface is furnished with a strong spine on each side near the distal end. The 

 second segment is asymmetrical. The distal end is provided with a doublé pointed process. 

 The anal segment is asymmetrical. It is much shorter on the right side than on the left. The 

 distal end of the first and second segments, and the ventro-lateral surface of the second segment, 

 is fringed with fine spines (Plate LI, figs. i and 2). The furcal joints are asymmetrical. The 

 right iurcal joint is much broader, and slightly longer than the left furcal joint. 



The antennules are composed of twenty-four joints and extend to the end of the anal segment. 



The antennae, mandibles, maxillae and maxillipedes are similar to those of the male. 

 The apical portion of the second maxillipedes is four-jointed. 



The exopodites of the four pairs of swimming feet are three-jointed. The endopodites 

 are two-jointed. 



The fifth pair of feet is slightly asymmetrical. The right exopodite is rather shorter and 

 stouter than the left. Each exopodite is armed with three outer edge spines. The distal part 

 of the inner margin bears two spines set close together. The proximal spine of this pair is 

 longer and stouter than the distal one. The apex terminates in a strong and slightly curved 

 spine. The endopodite of each foot is short. The apex is very feebly bifurcate. The figure 

 shews the fifth pair in a reversed position (Plate LI, fig. 6). 



Length of 'Siboga' specimens, female 1,95 mm., male 1,7 mm. 



Professor Brady described the species as a Pontella. Giesbrecht placed it in the o-enus 

 Labidocera on account of the two-jointed endopodite of the first pair of feet. Brady and 

 Wolfexdex appear to be the only authors who have hitherto met with this form. 



5. Labidocera minuta Giesbrecht. 



Labidocera minutum Giesbrecht, 1889, p. 27. 



Labidocera minutum Giesbrecht, 1893, p. 446, pi. 23, 25 & 41. 



Labidocera minuta Giesbrecht & Schmeil, 1898, p. 137. 



Labidocera minutum Cleve, 1901, p. 7. 



Labidocera minuta A. Scott, 1902, p. 407. 



Labidocera minuta Thompson & Scott, 1903, p. 251. 



Labidocera minutum Cleve, 1903, p. 363. 



Labidocera minuta Wolfenden, 1905 (a), p. 1018, pi. XCVIII, figs. 18, 24, 25, 29, 32, ^~. 



Eighteen females and nine males belonging to this species were obtained from the 

 plankton collected at the following stations. 



Stat. 16. — Stat. 35. — Stat. 37. — Stat. 47''. — Stat. 66. — Stat. 71. - Stat. 81. — Stat. 96 

 (night). — Stat. 106. — Stat. 109. — Stat. 110. -- Stat. 128 (HENSEN vertical net, 700 

 metres to surface). — Stat. 136. — Stat. 138. - - Stat. 141 (Hensex vertical net, 1500 

 metres to surface). — Stat 142. — Stat. 143 (Hexsex vertical net, 1000 metres to sur- 

 face). — Stat. 144. — Stat. 169. — Stat. 174. -- Stat. 189". -- Stat. 204. -- Stat. 205. - 

 Stat. 213. — Stat. 216. — Stat. 229. — Stat. 315. 



167 



