38 



being of almost equal width throughout and transversely truncated behind. 

 Caudal rami very short, being scarcely as long as they are broad, and sub- 

 quadrate in form, with the outer edge densely hairy; apical setae rather strong, 

 the 2 middle ones considerably longer than the others and conspicuously 

 dilated at some distance from the base; bristle of outer edge occurring close 

 to the apex. Anterior antennas fully as long as the cephalic segment, and 

 having the setae rather long and slender. Posterior antennae of the usual 

 structure, with the terminal joint about the length of the other 2 combined. 

 1st pair of legs with the rami of nearly equal length, terminal joint of the 

 outer one bent abruptly outwards, at nearly a right angle to the preceding 

 part; joints of inner ramus triangularly produced at the end outside. Last 

 pair of legs very small, with the proximal joint extending inwards as a narrow 

 band-like plate finely spinulose at the edge, digitiform process recurved; distal 

 joint comparatively small and subfusiform in shape, being conically produced 

 at the end, spine of inner edge occurring about in the middle. 



Body in the living animal rather pellucid, with the ovarial tubes and the 

 ripe ova of a bright grass-green colour. 



Length of adult female scarcely exceeding 1.80 mm. 



Remarks. This is much the smallest of the species here recorded, and 

 may moreover at once be recognised by the very short caudal rami, as also, 

 when examined in the living state, by the bright green colour of the ovarial 

 tubes and the ripe ova. The form recorded by Buchholtz from the Mediter- 

 ranean under the name of N. pusilla is quite certainly identical with 

 Thorell's species. 



Occurrence. I have taken this form, often in considerable number, from 

 the branchial cavity of several kinds of Ascidians, most frequently however in 

 Phallusia menliila. It seems to be distributed along the whole south and 

 west coasts of Norway, at least to the Trondhjem Fjord. 



Distribution. Coast of Bohuslan (Thorellj, British Isles (Brady), Mediter- 

 ranean (Buchholtz). 



Gen. 2. Agnathaner, Canu, 1892. 



Generic Characters. Body (of male) resembling in shape that in Noto- 

 delphys, being quite straight, with the anterior division somewhat dilated and 

 well marked off from the posterior; the latter narrow and composed of 5 seg- 

 ments. Caudal rami sublinear in shape, with the normal number of setae. 



