of the Fisher 1/ Hoard for Scotland. 455 



point, and not abruptly as in O. plumifera, Baird. This same Oifhona 

 was recorded from the Firth of Forth in 1891 under Dana's name — 

 Oithona setiyer* 



ASCIDICOLID.E. 



Dorcpygus normani, G. S. Brady. 



1898. Doropygus normani, G. S. Brady, Mon. Brit. Gopep., 

 vol. i., p. 136, pi. xxxii., 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. 



Platypsyllus, T. Scott (gen. nov.). 



Body flat and sub-ovate. Anteunules rudimentary. Antennsj 

 (?) obsolete. Mouth consisting of a small suctorial tube. Mandibles, 

 rnaxilh^?, and maxillipeds (?) obsolete. No thoracic feet observed. Abdo- 

 men scarcely distinguishable from the thorax. Ovisacs two, elongated. 



Platypsyllus minor, T. Scott (sp. nov.). PI. XXV., figs. 15-16. 



Description of Female. — Length 1'7 mm. (nearly -^.- 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 seta\ Antennse 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, thera was at first considerable doubt 

 regarding them, but ere long a sjjecimen 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.). PI. XXV., figs. 8-14. 



Description of the Female. — Length, 1-6 mm. (about -^ 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. 



