NOTES ON SOME RARE COPEPODA FROM SCOTLAND 237 



inner group are all elongate and plumose, the middle one being 

 rather longer than the other two ; the outer group consists of one 

 elongate and two very short seta?. The secondary joint is narrow, 

 subcylindrical, and extends somewhat beyond the end of the basal 

 joint ; it also bears six seta; three on the distal half of the outer 

 margin, one small seta on the inner margin, and two apical setae, one 

 of which is long and stout and one very short (Fig. 19). The caudal 

 stylets are short, and the anal operculum carries a fringe of short 

 bifid spines on the posterior margin (Fig. 20). 



Habitat. Loch Leven, Kinross-shire, along with Canthocamptus 

 sch)iieilii, but not nearly so common. 



REMARKS. This is a more typical Canthocamptus than the one 

 previously described, and may be distinguished from other species 

 of the same group by the structure of the first pair of swimming 

 feet, as also by the bifid spines on the anal operculum, which 

 appear to be peculiar to this species. 



Loch Leven is, so far, the only Scotch locality where Cantho- 

 camptus minutus has been obtained ; but since its discovery in Loch 

 Leven we have obtained information of its occurrence in several 

 localities in England. Mr. D. J. Scourfield obtained it last year at 

 Wanstead Park and in the Isle of Wight, and this year in Wales ; 

 while one of the authors of the present memoir (Mr. A. Scott) has 

 recently discovered it in a marshy drain near Leasowe Lighthouse, 

 Cheshire. 



The genus Canthocamptus, as described by several authors, 

 seems to us to be too inclusive, and to contain forms so diverse in 

 structure that a revision of the genus will ere long become neces- 

 sary in order to facilitate the study of the various divergent species 

 of which it is composed. We need only refer to the following 

 among other diversities of structure to show how heterogeneous are 



o o 



the forms at present included in this genus. Thus, for example, in 

 some species the secondary branches of the antennae (posterior 

 antennae) are one-jointed, and in others two-jointed. In some 

 species again the inner branches of the first pair of swimming feet 

 are composed of two equal or nearly equal joints, while in others 

 they are three-jointed : these inner branches are in various species 

 either equal in length to, or considerably longer than, the outer 

 branches. Moreover, in some species the inner branches of all the 

 first four pairs of swimming feet are two-jointed or three-jointed, 

 while in some the inner branches of the first pair or the first two or 

 three pairs are three-jointed, and of the other pairs two-jointed. In 

 1880 Dr. Brady established the genus Attheyella for one or two 

 aberrant forms of the Canthocamptiiuz ; but objection is taken by 

 Continental authors to this genus, who regard it as synonymous 

 with Canthocamptus. But Canthocamptus as it at present stands is 

 not, as we have indicated, a very satisfactory genus. 



