922 DR THOMAS SCOTT ON THE 
freely in the open sea. Such free-swimming species are subject to dispersal over wide 
areas by tidal and other currents, and numerous examples of such dispersal are indicated 
or described by various authors; but the wide distribution of an Harpactid such, for 
example, as Orthopsyllus linearis, Claus, may not be so easily explained. This Copepod 
is one of a group which have an elongated and moderately slender body, provided with 
short appendages that are scarcely, if at all, fitted for swimming, but are rather adapted 
for living among branching zoophytes or on the roots and stems of seaweeds. The 
transporting action of currents can have much less effective influence on the distribution 
of such species than on species living a free life in the open sea. Nevertheless, 
Orthopsyllus linearis has been recorded from the British Islands, from Norway, the 
Mediterranean, the Suez Canal, the Gulf of Manaar, and the Gulf of Guinea. More 
recently it has been obtained in material collected in the Malay Archipelago during the 
Siboga Expedition of 1899-1902,* and now this non-swimming species is here recorded 
from gatherings collected by the Scotwa among the South Orkney Islands. 
Another species—A sterocheres suberites, Giesbrecht—belonging to a different group 
of Copepods, is usually found living as a commensal in the water passages of certain 
sponges. t 
The wide dispersal of this Asterocheres cannot, from its peculiar habitat, be to any 
large extent attributed to oceanic currents, yet it has been recorded from the British 
Islands and the Mediterranean ; and one or two specimens from a gathering collected 
among the South Orkneys by the Scotza can scarcely be distinguished from those 
living on British sponges. Other species equally interesting and showing the near 
relationship of the non-pelagic Copepoda of the far South with those of our Northern 
Seas will be noticed in the sequel, but two may be briefly referred to here. One of them 
—an Harpactid, obtained in a small gathering of minute Molluscan shells collected on 
the shore at Port Stanley, Falkland Islands—has a remarkable likeness to a species that 
was dredged in the Firth of Forth off St Monance in 1891,{ and which has been 
described more recently by G. O. Sars from Norwegian specimens.§ The female of this 
species is distinguished by having the last pair of thoracic legs large and leaf-like,— 
hence the generic name Phyllopodopsyllus. The other form is also interesting because it 
may be regarded as supplying a “missing link” in the little group of nearly related 
species representing four genera, viz—Cervinia, Norman, Cerviniopsis, G. O. Sars, 
Zosime, Boeck, and Pseudozosime, Scott. In the first genus the inner ramus of the first 
pair of thoracic legs is three-jointed and that of the next three pairs two-jointed ; in the 
second all the four pairs of thoracic legs have the inner ramus three-jointed. In the 
third. the inner ramus of the first pair is two-jointed, and that of the next three pairs 
three-jointed ; while in Pseudozosime the inner ramus of all the four pairs is composed of 
* The Copepoda of the “ Siboga” Expedition, by ANDREW Scott, A.L.S., p. 225 (1909). 
+ Fauna u. Flora des Golfes von Neapel, 25. Monogr., “Asterocheriden,” by Dr W. GIESBRECHT, p. 70. 
t Tenth Annual Report of the Fishery Board for Scotland, part iii. p. 253, pl. ix. figs. 19-32. 
§ An Account of the Crustacea of Norway, vol. v. part xix. (1907), p. 231, pl. clv. 
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