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Pleuromamma gracilis Cleve, 1904, p. 195. 
Pleuromamma gracilis Wolfenden, 1905(@), p. 1012. 
Pleuromamma gracilis Sars, 1905(6), p. 2. 
Pleuromamma gracilis Esterly, 1905, p. 175, fig. 33 (Cc). 
Pleuromamma gracilis Farran, 1908, p. 61. 
Pleuromamma gracilis van Breemen, 1908, p. 106, fig. 122. 
This Pleuromamma proved to be almost as numerous, and nearly as widely distributed 
as the previous species. It was found in the plankton collected by the ‘Siboga’ at the following 
stations. 
Stat. 37. — Stat. 40. — Stat. 66. — Stat. 71. — Stat. 75 (HENSEN vertical net, 11 metres 
to surface). — Stat. 81. — Stat. 96 (night). — Stat. 117°. — Stat. 118 (HENSEN vertical 
net, goo metres to surface). — Stat. 128 (HENSEN vertical net, 700 metres to surface). — 
Stat. 141 (HENSEN vertical net, 1500 metres to surface). — Stat. 143 (HENSEN vertical 
net, [000 metres to surface). — Stat. 144. — Stat. 146. — Stat. 148 (HENSEN vertical net, 
1000 metres to surface). — Stat. 185 (HENSEN vertical net, 1536 metres to surface). — 
Stat. 189°. — Stat. 203 (HENSEN vertical net, 1500 metres to surface). — Stat. 204. — 
Stat. 216. — Stat. 225. — Stat. 230 (HENSEN vertical net, 2000 metres to surface). — 
Stat. 243 (HENSEN vertical net, 1000 metres to surface). — Stat. 245. — Stat. 276 (HENSEN 
vertical net, 750 metres to surface). — Stat. 304. — Stat. 315. 
The luminous organ in this species is present on the right side only. The left antennule 
of the male is modified for grasping. The fifth pair of feet of the female is composed of a 
single joint attached to a basal part. The apex of the free joint is furnished with three short spines. 
This species appears to be nearly as widely distributed as the previous form. 
Some of Brapy’s figures in the report on the ‘Challenger’ Copepoda refer to Pleuro- 
mamma gracilis. 
3. Pleuromamma xiphias (Giesbrecht). 
Pleuromma xiplias Giesbrecht, 1889, p. 25. 
Pleuromma xiphias Giesbrecht 1893, p. 347, pls. 32 & 33. 
Pleuromamma xiphias Giesbrecht & Schmeil, 1898, p. 109. 
Pleuromamma xtphias Thompson & Scott, 1903, p. 249. 
Pleuromamma xiphias Cleve. 1904, p. 195. 
Pleuromamma xiphias Wolfenden, 1905 (a), p. 1012. 
Pleuromamma xiphias Sars, 1905(0), p. 2. 
Pleuromamma xiphias Esterly, 1905, p. 176, fig. 34. 
Pleuromamma xiphias Farran, 1908, p. 61. 
Pleuromamma xiphias van Breemen, 1908, p. 105, fig. 120. 
This species although represented in fewer plankton samples than either of the other 
two was moderately frequent where it did occur. It was noted at the following stations. 
Stat. 117%. — Stat. 118 (HENSEN vertical net, 900 metres to surface). — Stat. 128 (HENSEN 
vertical net, 700 metres to surface)..— Stat. 141 (HENSEN vertical net, 1500 metres to 
surface). — Stat. 143 (HENSEN vertical net, 1000 metres to surface). — Stat. 148 (HENSEN 
vertical net, 1000 metres to surface). — Stat. 184. — Stat. 185 (HENSEN vertical net, 1536 
metres to surface). — Stat. 189°. — Stat. 203 (HENSEN vertical net, 1500 metres to sur- 
face). — Stat. 216. — Stat. 220 (HENSEN vertical net, 200 metres to surface). — Stat. 243 
(HENSEN vertical net, 1000 metres to surface). — Stat. 276 (HENSEN vertical net, 750 
metres to surface). — Stat. 304. 
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