232 
Two species are at present known. One was represented in the plankton collected by 
the ‘Siboga’ in the Malay Archipelago. 
1. Clytemnestra rostrata (Brady). 
Goniopsyllus rostratus Brady, 1883, p. 107, pl. XLII, figs. 9—16. 
Clytemnestra rostrata Giesbrecht, 1893, p. 566, pl. 45. 
Clytemnestra rostrata Wheeler, 1900, p. 189, fig. 26. 
Clytemnestra rostrata Thompson & Scott, 1903, p 258. 
Clytemnestra rostrata Esterly, 1905, p. 214, fig. 54. 
Clytemnestra rostrata Norman & T. Scott, 1906, p. 140. 
Clytemnestra rostrata Farran, 1908, p. QI. 
Clytemnestra rostrata van Breemen, 1908, p. 180, fig. 194. 
Four males and one female identical with the species described by Professor G. S. Brapy 
in the report on the ‘Challenger’ Copepoda, were obtained from the plankton collected at the 
following stations. 
Stat. 81, 1 male. --- Stat. 142, 1 male. — Stat. 174, 1 female. — Stat. 213, 1 male. — 
Stat. 304, 1 male. 
GIESBRECHT in his great work distinguishes the female of C7lytemmnestra rostrata (Brady) 
from Clytemnestra scutellata Dana by the proportional length of the joints of the antennules. 
The second last joint of the antennules of Clytemmnestra rostrata is very distinctly shorter than 
the third last joint. Its length is contained nearly six times in the length of the last joint. 
The second last joint of the antennules of CZlytemnestra scutellata is slightly longer than the 
third last joint. Its length is contained twice in the length of the last joint. 
Clytemnestra rostrata appears to have a moderately wide distribution in the great oceans, 
but some of the records of its occurrence are perhaps doubtful. The species recorded by my 
father from the Gulf of Guinea as CZlytemmnestra rostrata is evidently identical with Dana’s 
species as the illustration of the female antennule is similar to the figure given by GIEsBRECHT. 
39. Family PoNTOSTRATIOTIDAE nov. 
The body is provided with a well defined sharp pointed rostrum. The principal furcal 
seta is in the form of an extremely long slender setiferous spine, with a jointed distal end 
carrying a plumose seta. The antennules are six to eight-jointed. The distal end of the upper 
margin of the first joint is produced into a knob. The exopodite of the antennae is short and 
one to four-jointed. The mandibles, maxillae and maxillipedes are well developed. The second 
pair of maxillipedes is not prehensile. The exopodite and endopodite of the four pairs of feet 
are three-jointed. The fifth pair of feet is elongate and two-jointed. 
The type of this family is Pontostratiotes abyssicola Brady 1883, and it includes the 
genus Aegzsthus Giesbrecht. The very pointed cephalic segment, and the extraordinary development 
of the principal furcal seta are quite sufficient to separate the members of this family from any 
of the other families belonging to the Harpacticoida. 
232 
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