36 



NILS HJ. ODHNER 



observed occasionally in true specimens of this species at the 

 margin of the rhinophores. 



The rad ula of the Dotonidae (fig. 14.) does not offer any 

 characters for distinguishing the species. In all forms the denticles 

 of the teeth are rather irregularly arranged, as also is remarked 

 by Bergh (1892).^ This irregularity in number and position is 

 observed in different teeth within the same radula as well as 

 in radulae of different individuals of the same species, which is 



O 





d 



Fig. 14. Radulae of Dotonidae. (cf. p 47). 



evident from the figures given here. A common characteristic is 

 the depression of the median cusp in relation to the denticles; 

 the sides of the teeth being greatly convex, and the denticles 

 projecting from above the margins, not from the very edges. 



Anatomy of Doto. 



As the anatomy of Doto has been only imperfectly studied 

 (by Alder & Hancock, Bergh, Trinchese, Pelseneer, and 

 Vayssière), and the relations of the genus thus are somewhat 

 uncertain, I have examined some specimens of D. , coronata 

 both^by means of dissection and on sections. Inan earlier publication 

 of 1914,^ I expressed the opinion, in dealing with the phylogeny 



^ Cf. note on p. 9. 

 2 Cf. note on p. 3. 



