22 
Eucalanus subtenuzs Giesbrecht & Schmeil, 1898, p. 21. 
Eucalanus subtenuis Cleve, 1901, p. 7. 
Eucalanus subtenuis A. Scott, 1902, p. 401. 
Eucalanus subtenuts Thompson & Scott, 1903, p. 242. 
Eucalanus subtenuis Cleve, 1903, p. 363. 
Eucalanus subtenuis Cleve, 1904, p. 190. 
Eucalanus sibtenuts Sars, 1905 (a), p. 2. 
Eucalanus subtenuzs Wolfenden, 1905 (a). p. 996. 
Eucalanus subtenuzs Esterly, 1905, p. 135, fig. 9. 
iS) 
Lucalanus subtenuts appeared to have a fairly wide distribution in the area traversed 
by the ‘Siboga’ as shewn by the following records. 
Stat. 47°. — Stat. 66. — Stat. 75. — Stat. 93. — Stat. 98. — Stat. 118. — Stat. 124. — 
Stat. 125 (day). — Stat. 125 (night). — Stat. 129. — Stat. 136. — Stat. 138. — Stat. 141. — 
Stat. 142. — Stat. 144. — Stat. 157. — Stat. 165.— Stat. 169. — Stat. 172. — Stat. 184. — 
Stat. 189%. — Stats. 1947. — Stat. 203 (surface). — Stat. 203 (1500 metres). — Stat. 204. — 
Stat. 205. — Stat. 214. — Stat. 215%. — Stat. 217 (horizontal cylinder). — Statt. 220 
(vertical net). — Stat. 245. 
Eucalanus subtenuzs has been recorded from the Atlantic, Pacific, and Indian Oceans 
and also from the Arabian Sea. 
A considerable amount of care is necessary to distinguish the last three species of 
Eucalanus from each other. The external characters are not very well marked, and the points 
of difference are frequently obliterated when the specimens are distorted. It is always wise to 
make dissections of the appendages before a definite conclusion is arrived at. 
7. Eucalanus dentatus nov. sp. Plate Il, figs. 1—8. 
Female — length 2,6 mm. 
The head is considerably contracted in front and is produced into a well-marked spiniform 
process. When viewed from the side, the spiniform process appears to be directed slightly 
upward, terminating in a sharp point, (Plate Il, fig. 2). The fourth and fifth thoracic segments 
are completely separated. The last thoracic segment has rounded extremities. The apex of the 
last thoracic segment is greatly contracted and is very little wider than the base of the genital 
segment. The abdomen is three-jointed and symmetrical, with one free segment between the 
genital’ and anal segments. 
The antennules are twenty-three jointed, and extend beyond the end of the furca by 
five joints. 
The antennae are nearly as in Ewcalanus crassus. The proximal joint of the endopodite 
is about double as long as broad. 
The mandible palp is furnished with two inner setae on the second joint of the basio- 
podite. The first joint of the endopodite is destitute of setae, and the second joint is furnished 
with four apical setae. The exopodite is apparently without segmentation, and is furnished with 
six setae on the distal end. 
The maxillae and maxillipedes are nearly as in Ewcalanus attenuatus. The first and 
second joints of the endopodite of the second maxillipedes are furnished with four setae. 
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