Gatty Marine Laboratory , St. Andrews. 35 



in lateral view, whereas in Euchone analis the number of 

 teeth is nearly doubled, and a differentiation of this region 

 from that of the great fang is evident. The base is curiously 

 diminished and narrowed posteriorly, but the prow is large 

 and rounded. The posterior hooks are even more diagnostic 

 than the anterior. The posterior outline is convex, with a 

 slight inflection below the crown, and a short posterior curve 

 at the base, which is small. The great fang is long and 

 sharp, and on the crown above it are six or seven distinct 

 teeth. Tlie anterior outline begins at a little less than a 

 right angle, gently curves forward to the prow, M^hicli 

 inferiorly blends with the short trnucate base. The lower 

 part of the neck and body have curved stride. In structure, 

 therefore, these hooks differ from those of E. analis, Kroyer, 

 and E. papulosa, Sars. Neither is figured by Mahngren. 



The representatives of the genus Chone in northern waters 

 seem to be in a somewhat confused condition, since the 

 young of certain forms have been described as different 

 species. At least five species, however, are clearly defined, 

 viz. the characteristic Chone infundlbuUformis, Kroyer, of the 

 arctic seas, which appeal's to be rare in most collections, but 

 was procured by the 'Valorous' in 1875. This form has 

 often been confounded with another species, viz. Chone 

 duneri, Malmgren — indeed, in a named collection from 

 Greenland, procured in the sixties of last century, it is 

 labelled C. iyifandibuUformis. Yet the form of the tips 

 of the branchiae in the latter, the structure of its hooks, 

 especially the avicular posterior hooks, the bristles, and other 

 features are diagnostic. 



The original description of C. infandibuliformis by Kroyer'^, 

 although unfortunately he gives no figure, is clear in regard 

 to the structure of the branchiae, the collar, the size, and 

 other features. He adds that it is not rare in Greenlandic 

 seas, and that it inhabits a cuticular tube devoid of mud ; 

 yet modern naturalists seem to have seldom met with it. 

 Its posterior hooks are so characteristic that no confusion 

 with C. duneri need occur — even in young forms of each 

 species. Of course, it may be a question what form Kroyer 

 meant by his C. infundibuliformis, since both it and C. duneri 

 are found in the arctic seas, but the typical C. infundlbuU- 

 formis is chiefly arctic in distribution, whereas C, duneri has 

 a much wider range. After careful consideration of Maim- 

 gren's views and various specimens, it has been deemed 

 prudent to adhere to the diagnosis indicated above. It is, 

 however, right to state that Prof. Fauvel and others hold 



* Oversigt Kgl. daiiske Videnskub. Selskabs Forhandl. 1856-57, p. 33. 



3* 



