11 



water. The specimens will then at once make their appearance, owing to a pecu- 

 liarity which they have in common with some other Copepoda, namely, that on 

 touching the surface, they remain floating upon it. The swimming movements of 

 the animal are rather rapid, and constitute an even progress through the water. 

 When keeping to the bottom, it may, however, propel itself in a more abrupt, 

 jerky manner, by employing the long inner rami of the 2nd pair of legs like a 

 pair of leaping-poles. 



Distribution. Heligoland, Gulf of Naples (Glaus). 



3. Longipedia Scotti, G. 0. Sars, n. sp. 



(PI. V, fig. 1). 

 Syn: Longipedia coronata, Brady, Scott (not Claus). 



Specific Characters. Female. Very like the preceding species, but ot 

 somewhat larger size, and perhaps more robust form of body. Posterior edge of 

 caudal segments fringed throughout with delicate denticles. Anal opercle with 

 one large and 4 smaller denticles on each side, terminal spine very strong. 

 Caudal rami about as in L. coronata, the apical setae being very strong and dark- 

 coloured, though perhaps somewhat shorter than in that species. Inner ramus of 

 2nd pair of legs with the inner proximal spine of the terminal joint placed behind 

 the spine of the outer edge, the latter occurring in front of the middle; distal 

 inner spine generally turned outwards. Last pair of legs with the distal joint 

 sub-spatulate in form, gradually widening towards the tip, inner expansion of 

 proximal joint with a very small hair-like spinule inside the base of the ter- 

 minal seta. 



Colour yellowish gray. 



Length of adult female reaching 1.50 mm. 



Remarks. This is the form recorded by Brady 1 ) and Scott as L. coro- 

 nata Claus. In one of his numerous papers, Th. Scott has called attention to a 

 character in which the present form differs conspicuously from another smaller 

 form, at first only regarded by him as a variety (var. minor) of Claus's species. 

 This character consists in the different position of the inner proximal spine on 

 the terminal joint of the inner ramus of the 2nd pair of legs. The author seems, 

 however, to have been unaware of the fact that in Claus's species this spine has 



*) As first pointed out, however, by Th. Scott, Brady has under this name confounded 

 2 very different Copepods, not even belonging to the same genus, only that regarded by him 

 as the male being referable to the present species. 



