568 DR THOMAS SCOTT ON THE 
with a tolerably stout, short, but prominent tooth on the lower aspect, while the third 
joint carries a moderately long sensory filament. Antenne small; outer ramus uni- 
articulate. Mandibles small and provided with a small one-branched palp. 
Thoracic legs small. In the first pair, the inner ramus is rather longer than the 
outer, and the proximal joint is nearly twice as long as the end one. In the next three 
pairs, the inner ramus is very short, and the proximal joint extremely small (see 
figs. 16-19). 
The fifth pair has the basal joint tolerably broad and lamelliform, and produced 
interiorly to near the end of the second joint; the distal half of the inner margin of the 
basal joint is obliquely and somewhat unevenly rounded, and furnished with five sete, 
three on the inner margin and two at the apex; the second joint is moderately 
narrow, its width at the widest part being scarcely equal to half the length: this 
joint bears six sete; the apical seta is tolerably stout and elongated, but the one on 
either side of it is small; the other three sete, which are of moderate length, spring 
from the outer margin, as shown in the drawing (fig. 20). 
Male.—In the male, the antennules are modified to form grasping organs. The 
inner ramus of the second pair of thoracic legs is three-jointed, and the second joint is 
produced into a long and tolerably stout spiniform appendage (fig. 21). In the fifth pair, 
which are very small, the basal joint is scarcely produced interiorly, and is provided 
with two short sete; the outer jot is short and narrow, and furnished with three 
small setee on the outer margin and two at the apex (fig. 22). 
Habitat.—Scotia Bay, South Orkneys, in siftings from some dredged material 
collected in June 1903; Station 325, 60° 43’ 42” S., 44° 38’ 33” W. 
Remarks.—This species, though not very common, has apparently an extensive 
distribution. Professor G. O. Sars records it from Skjzerstad Fjord in Norway—just 
within the Arctic Circle, and Dr G. 8. Brapy from a few British localities. Dr CLaus 
obtained the species in the Mediterranean, and it also occurred in collections from the 
Gulf of Guinea brought home by the telegraph steamer Buccaneer. After a careful 
examination of the South Orkney specimens, I.am unable to discover any essential 
difference between them and those described by the authors mentioned above. 
Tribe CYCLOPOIDA. 
Fam. OrrHoNIDz. 
Genus Ozthona, Baird, 1848. 
Orthona plumifera, Baird. 
1843, Oithona plumifera, Baird, ‘“‘ Notes on British Entomostraca,” Zoologist, vol. i. pp. 193-197. 
This species was observed in gatherings from various stations, extending from 
Station 11, 23° 50’ N., 21° 34’ W., in the North, to Station 68 in the South Atlantic, 
Pernambuco, 7° 42’ S., 34° 32’ W. Its distribution, which is widely extended, reaches 
to at least as far north as the British Islands. 
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