ENTOMOSTRACA OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 567 
tioned they are elongated. The length of the specimen represented by the drawing 
(fig. 1) is 0°62 mm. (45 of an inch). 
Antennules tolerably slender, and composed of five joints, the penultimate being 
very small. Antenne small ; outer ramus wanting. 
Mandibles and other mouth-organs nearly as in Laophontodes typicus ; the second 
maxillipeds are slender, and are each provided with a long and slender terminal claw. 
The first pair of thoracic legs resemble those of the species mentioned, and the 
next three pairs are also similar to those in the same species. In the second, third, and 
fourth pairs, the inner ramus is short, two-jointed, and very slender, the first joint being 
very small; the imner ramus of the pair is, however, proportionally rather more 
elongated than the others. 
In the fifth pair, the basal joint is rather longer than the second one, and both are 
provided with a few setz. 
Caudal rami short, scarcely longer than the last segment of the abdomen. 
Habitat.—Scotia Bay, South Orkneys, in some siftings from dredged material 
collected in June 1903; Station 325, 60° 43’ 42” §., 44° 38’ 33” W. 
Remarks.—The form described above may be at once recognised from any previously 
described species by its short candal rami; it is also rather more slender and elongated 
than any of those previously described. 
Its occurrence in the Scotia collections is a further indication of, in some respects, 
the close similarity between the Copepod fauna of the Antarctic and that of our 
northern seas. G. O. Sars has recorded three species of Laophontodes from the coasts 
of Norway, and two of them also occur in British waters. Moreover, one of these 
northern forms (Laophontodes typicus) was also collected by Dr Brucr as far north as 
Franz Josef Land. All the three northern species are provided with long caudal 
rami, and are thus readily distinguished from the one now described. This species is 
named in compliment to Mr T'Homas B. Wuitson, a member of Committee and 
Honorary Accountant to the Expedition. 
Fam. CLETODIDA. 
Genus Orthopsyllus, Brady & Robertson, 1873. 
Orthopsyllus linearis (Claus). (PI. IX. figs. 10-22.) 
1866, Liljeborgia linearis, Claus, Die Copepoden-fauna von Nizza, p- 22, t. ii. figs. 1-8. 
1873, Orthopsyllus linearis, Brady & Robertson, Ann. and Mag. Nat. Hist., vol. xii. p. 138. 
1880, Cletodes linearis, Brady, Monogr. Brit. Copep., vol. ii. p. 95, pl. lxxx. figs. 1-14. 
1909, Orthopsyllus linearis, G. O. Sars, Crust. of Norway, vol. v. p. 289, pl. excix. 
Female.—The body, viewed from above, is narrow and elongated; the posterior 
margins of the segments are dentated; rostrum blunt and slightly produced. Caudal 
rami short ; each ramus is provided witha stout and tolerably elongated terminal bristle. 
The specimen represented by the drawing (fig. 10) measures about 1°7 mm. in length. 
The antennules are short and composed of four joints; the second joint is armed 
