141 
2. Haloptilus ornatus (Giesbrecht). 
Hemicalanus ornatus Giesbrecht, 1893, p. 384, pls. 27 & 42. 
Haloptilus ornatus Giesbrecht & Schmeil, 1898, p. 120. 
Haloptilus ornatus 1. C. Thompson, 1903, p. 28. 
Haloptilus ornatus Sars, 1905(0), p. 4. 
Flaloptilus ornatus van Breemen, 1908, p. 130, fig. 148. 
One specimen of this H/aloptz/us was found in the plankton collected with the HEnsEN 
vertical net at each of the following stations. 
Stat. 118 (900 metres to surface). — Stat. 128 (700 metres to surface). 
This species can easily be separated from the other members of the genus by its narrowly 
rounded forehead, and by the strong curved spines on the apical lobes of the first pair of 
maxillipedes. The antennules extend beyond the end of the furca by about four joints. 
Haloptilus ornatus was originally described by Girssrecut from Mediterranean specimens. 
TuHompson, Sars and vAN BREEMEN have since recorded it from other areas. 
3. Hlaloptilus plumosus (Claus). 
Hemicalanus plumosus Claus, 1863, p. 178, pls. XXVIII & XXIX. 
Hemicalanus plumosus Giesbrecht, 1893, p. 384. 
Hemicalanus plumosus T. Scott, 1893, p. 33, pls. II & VI. 
Flaloptilus plumosus Giesbrecht & Schmeil, 1898, p. I19. 
One specimen belonging to this species was found in the plankton collected with the 
HENSEN vertical net at Station 141, 1500 metres to the surface. 
Hlaloptilus plumosus resembles Hlaloptilus ornatus in general appearance. It can be 
distinguished by its shorter antennules, and by the endopodite of the maxillae being furnished 
with four setae. 
This species has hitherto only been known from the Mediterranean and from the Gulf 
of Guinea. 
4. Haloptilus spiniceps (Giesbrecht). 
Hemicalanus spiniceps Giesbrecht, 1893, p. 384, pls. 27 & 42. 
Haloptilus spiniceps Giesbrecht & Schmeil, 1898, p. 120. 
Flaloptilus spiniceps 1. C. Thompson, 1903, p. 28. 
Haloptilus spiniceps Sars, 1907 (a), p. 19. 
Haloptilus spiniceps van Breemen, 1908, p. 130, fig. 149. 
One specimen of this Haloptc/is was obtained from the plankton collected at each of 
the following stations. 
Stat. 128 (HENSEN vertical net, 700 metres to surface). — Stat. 185 (HENSEN vertical net, 
1536 metres to surface). — Stat. 203 (HENSEN vertical net, 1500 metres to surface). — 
Stat. 220 (HENSEN vertical net, 200 metres to surface). — Stat. 315. 
This species can readily be separated from the other members of the genus by the short, 
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