REPORT ON THE NEMERTEA. 3 



nemertea are as yet only on record from the Atlantic and the Mediterranean. It is, 

 however, very probable that these genera (the Carinellidas) are cosmopolitan, and have 

 as yet only escaped detection because even in the region from which they are known 

 they count among the rare forms. 



I have here only to add that in drawing up the list of the Challenger Nemertea, I 

 will follow the subdivision into larger groups that was proposed by myself several years 

 ago (VII, p. 204), 1 and will successively treat of the Palseonemertea, Hoplonemertea, and 

 Scbizonemertea. It may be remarked that in the first named group, which contains the 

 most primitive and least differentiated representatives, the genera Valencinia and Ewpolia 

 ( = Polio) were also provisionally placed. These two may be looked upon as, to a 

 certain degree, transitional forms. New light has been thrown by the Challenger 

 material upon at least one of these genera, and it appears advisable to let them stand in 

 that subdivision, however far they may differ in certain respects from the typical 

 Palseonemertea, such as Carinella, Carinoma, Carinina, &c, and however strong their 

 affinities may be in other respects either to the Scbizonemertea or to the Hoplonemertea. 



1 The heavy numerals refer to the Bibliography at the end of the Report. 



