441 



the proximal joint subfusiform in shape and much larger than the distal one, 

 the latter provided inside near the base with a moderately long seta, and at the 

 tip with a very long denticulated spine accompanied outside by a short spine, 

 inside by an ordinary seta. 4th pair of legs resembling in structure the 2 

 preceding pairs, except that the inner ramus is comparatively shorter and has 

 no seta inside the distal joint, whereas the terminal joint of the outer ramus is 

 provided inside with such a seta. Last pair of legs with the distal joint obli- 

 quely rounded and carrying outside 3 short spines and at the tip a slender seta; 

 inner expansion of proximal joint very small, with only 2 slightly unequal seta? 

 on the transversely truncated extremity. Ovisac oblong oval in form, and attached 

 to the genital segment by a short stalk. 



^[ale only slightly differing from female, though having the anterior 

 antenna} hinged in the usual manner, and the last pair of legs less perfectly 

 developed. 



Colour pure white. 



Length of adult female 1.18 mm. 



Remarks. From its slender cylindrical body, this Copepod looks very 

 like the forms included in the family CylindropsyllidoB, and may at first sight 

 easily be mistaken for one or other of them. A closer examination will however 

 soon reveal some very essential differences in the structural details. Another 

 obvious difference is the presence in the female of only a single ovisac, whereas 

 in all the known Cylindrqpsyllidce, there are 2 such ovisacs. 



Occurrence. I found this remarkable Copepod last summer rather abundantly 

 at Korshavn in the same locality from which so many other interesting forms, 

 treated of in the preceding pages, were derived, the depth ranging from 30 to 50 

 fathoms. In the same locality also Cylindropsyllus Iwiis occurred rather frequently, 

 and the resemblance between these 2 forms in size and general appearance was 

 very striking. 



Distribution. Scottish coast (Scott), 



