193 
Occurrence. — Two females were found in the plankton collected at Station 213. 
The fifth pairs of feet of the two specimens were identical. 
The triangular spine under each eye in the two species now described is readily seen 
when the Copepod is so placed that it rests midway between the dorsal and lateral positions. 
Tribe AMPHARTHRANDRIA. 
22. Family Mormoniiimae. 
Genus Mormonilla Giesbrecht, r8gr. 
The members of this genus are readily distinguished by their transparent, elongate 
narrow body, by the slender abdomen, and by the long furcal joints. The antennules are 
composed of three or four joints, and are furnished with very long setae. The structure of the 
other appendages is also characteristic of the genus. 
One species was represented in the plankton collected by the ‘Siboga’. 
1. Mormonilla phasma Giesbrecht. 
Mormonilla phasma Giesbrecht, 1891, pp. 474 & 475. 
Mormonilla phasma Giesbrecht, 1893, p. 532, pl. 43. 
Mormonilla phasma T. Scott, 1893, p. 64, pl. VII, figs. 11—21. 
Mormonilla phasma 1. C. Thompson, 1903, p. 31. 
Mormonilla phasma Farran, 1908, p. 88. 
Mormonilla phasma van Breemen, 1908, p. 166, fig. 181. 
Six females belonging to this species were obtained from the plankton collected at the 
following stations. 
Stat. 118 (HENSEN vertical net, 900 metres to surface), 2 specimens. — Stat. 143 (HENSEN vertical 
net, 1000 metres to surface), 2 specimens. — Stat. 203 (HENSEN vertical net, 1500 metres 
to surface), I specimen. — Stat. 205, I specimen. 
of this species is equal to very little more than half 
The last joint of the antennules 
Mormonilla minor Giesbrecht, the last joint of the 
the length of the second last joint. In 
_antennules is as long as the second last joint. 
Mormonilla phasma has been recorded from the Atlantic and Pacific Oceans. 
23. Family OITHONIDAE. 
Genus Oithona Baird, 1843. 
The members of this well known genus are readily recognised by the very elongate ovate 
and transparent body, and by the moderately long abdomen. The structure of the mandible 
palp and of the second pair of maxillipedes is quite distinct from that found in Cyclops. This 
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