of the Fishery Board for Scotland. 455 
point, and not abruptly as in O. plumifera, Baird. This same Ozthona 
was recorded from the Firth of Forth in 1891 under Dana’s name— 
Oithona setiger.* 
ASCIDICOLIDA, 
Doropygus normani, G. 8S. Brady. 
1898. Doropygus normant, G. S. Brady, Mon. Brit. Copep., 
vol. 1., p. 136, pl. xxxul., figs. 1-14. 
This large and distinct species was obtained in some material dredged 
in 8 fathoms off the North Craig, Firth of Forth, on July the 4th, 1901. 
Though the branchial chamber of the larger ascidians is the usual habitat 
of this species, it sometimes happens that the test of the ascidian is rup- 
tured by the dredge, and the copepods that may be contained within the 
branchial chamber are then set free. Probably this may explain the 
reason why the specimens of a somewhat peculiar type of copepod, which 
I now describe, were obtained “free” amongst the same dredged material 
from the North Craig in which the Doropygus occurred. 
tha. / Platypsylls, T. Scott (gen. nov.), 
Body flat and sub-ovate. Antennules rudimentary. Antenne 
ils (2) obsolete. Mouth consisting of a small suctorial tube. Mandibles, 
eu fii) maxille, and maxillipeds (?) obsolete. No thoracic feet observed. Abdo- 
men scarcely distinguishable from the thorax. Ovisacs two, elongated. 
Platypsyllus minor, T. Scott (sp. nov.). Pl. XX’V., figs. 15-16. 
Description of Female.—Length 1:7 mm. (nearly ts of an inch) in 
length. Body, seen from above, flat, oblong-ovate, greatest width near the 
posterior end, but the form varies somewhat in different specimens. 
Colour (after a short immersion in alcohol), opaque-white. Antennule 
obsolete or nearly so, reduced to a minute lobe on each side of the fore- 
head, and bearing one or two extremely minute sete. Antenne obso- 
lete. Mouth suctorial, and consisting of a small trumpet-shaped tube 
(fig. 16). Mandibles and other mouth appendages wanting. Thoracic 
feet also wanting. Abdomen indistinct from thorax. Ovisacs two, 
elongated, and containing numerous small ova; each ovisac originates 
from a small lateral angular process at the posterior end of the body 
(fig. 15). 
Habitat.—Vicinity of North Craig, Firth of Forth, dredged in 8 
fathoms on July 4th, 1901. No males have been observed. 
Remarks.—The first specimens of this curious copepod observed were 
without ovisacs, and from their shape, their colour, and the apparent 
entire absence of appendages, there was at first considerable doubt 
regarding them, but ere long a specimen turned up with two long ovisacs 
attached to it, and then their true character was revealed. 
From the simple and unarmed structure of these copepods it is fairly 
evident, I think, that if they are not commensals of some ascidian they 
must receive from some other host the shelter and protection necessary 
to organisms apparently so helpless as these animals seem to be. 
Nereicola concinna, T. Scott (sp. nov.). Pl. XXV., figs. 8-14. 
Description of the Female.—Length, 1°6 mm. (about 54 of an inch) 
Body considerably dilated, rather more than one.and a half times longer 
* Ninth Annual] Report of the Fishery Board for Scotland, Part III., p. 301. 
