146 
Stat. 141 (HENSEN vertical net, 1500 metres to surface), 2 females. — Stat. 142, 2 males. — 
Stat. 148 (HENSEN vertical net, 1000 metres to surface), 8 females and five males. — Stat. 
185 (HENSEN vertical net, 1536 metres to surface), 2 females and 1 male. — Stat. 203 
(HENSEN vertical net, 1500 metres to surface), 2 females and 4 males. 
Genus Metacalanus Cleve, 1go1. 
This genus was established mJi9o1 “by the late? Professor 2 i Grevmioneanscnill 
Calanoid found in plankton collected near the Island of Langkuss, N.W. of Billiton in the Malay 
Archipelago. It is nearly related to Arzefellus in the structure of some of the appendages. It 
also comes remarkably close to the genus Sco¢twla established by Professor G. O. Sars in 1902 
in ‘Crustacea of Norway’. 
The only obvious difference between this genus and Scottula, is in the structure of the 
female fifth pair of feet. The fifth pair in Sco¢twa has two free joints and a basal part. A/efacalanus 
has only one free joint and a basal part. | 
One species is known. It was well represented in the area investigated by the ‘Siboga’. 
1. Wetacalanus aurivilliz Cleve. 
Metacalanus aurivillit Cleve, 1901, p. 43, pls. IV & V. 
Metacalanus aurivillit Thompson & Scott, 1903, p. 243, pl. II. 
Males and females belonging to this species were found in the plankton collected at the 
following stations. 
Stat. 165) Stam19:,-— Stat..354-— | Stat y36.) 1 Statna7n Stata OnStar 
Stat. 66. — Stat. 75. — Stat. 93. — Stat. 96 (day). — Stat. 96 (night). — Stat. 98. — 
Stat. 99. — Stat. 106. — Stat. 109. — Stat. 117%. — Stat. 118 (HENSEN vertical net, 900 
metres to surface). — Stat. 125 (day). — Stat. 128 (HENSEN vertical net, 700 metres to 
surface). — Stat. 136. — Stat. 138. — Stat. 141 (HENSEN vertical net, 1500 metres to 
surface). — Stat. 142. — Stat. 143 (HENSEN vertical net, 1000 metres to surface). — Stat. 
148 (HENSEN vertical net, 1000 metres to surface). — Stat. 184. — Stat. 203 (HENSEN 
vertical net, 1500 metres to surface). — Stat. 205. — Stat. 213. — Stat. 217 (horizontal 
cylinder). — Stat. 220 (HENSEN vertical net, 200 metres to surface). — Stat. 252. — Stat. 
276 (HENSEN vertical net, 750 metres to surface). — Stat. 282. — Stat. 304. — Stat. 315. 
Metacalanus aurwillz is a very small Calanoid and is easily overlooked. The female 
is .65 mm. and the male .5 mm. in length. 
The right antennule of the male and female is distinctly shorter than the left. The fifth 
pair of feet of the female is composed of one free joint attached to a basal part. The free 
joint is broad and lamelliform. It is furnished with one outer marginal seta, one apical seta, 
and one long plumose inner marginal seta. The male fifth pair is quite symmetrical. It consists 
of four free joints attached to a basal part. The apical joint of the right and left foot is in 
the form of a long slender claw. The second and third free joints are each furnished with one 
outer marginal seta. The endopodite is absent. 
This species was obtained by Creve from plankton collected in the Malay Archipelago 
in 1899. It was present in the plankton taken at twenty-seven stations round the Island of 
Ceylon by Professor HERDMAN in 1903. 
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