338 ON A HERMAPHRODITE AND 



If, however, a portion of the calcareous mass be broken down, and 

 its delicate fabricators carefully extracted (fig. 3), their annelidan 

 nature becomes immediately obvious ; and in determining the exact 

 place of this form among the tubicola, the expanded membrane 

 which fringes the sides of the body, the peculiar branchial plumes, and 

 the absence of any operculum, would point at once to the genus 

 Protiila ^ as that to which this species belongs, were it not for two 

 most remarkable peculiarities of its organization, which, so far as we 

 know at present, are to be found in no Protula ; and one of them in 

 no other tubicolar annelid. 



These peculiarities are, in the first place, that this species under- 

 goes fissiparous multiplication ; and, in the second, that it is 

 hennaphrodite — the male and female reproductive elements being, 

 unequivocally, developed in the same individual. 



So far as I am aware, the process of fissiparous multiplication has 

 hitherto been observed in only one family among the errant annelids, 

 the Syllidea (of Grube) ; in only one family among the ScoleidcE 

 {Hirudinidce and LumbricidcB), that of the Naidea, — and in only one 

 genus among the tubicolar annelids, Filograna. 



Hermaphrodism has hitherto been observed in no errant or 

 tubicolar annelid.^ Indeed the author to whom we are indebted for 

 the most beautiful researches into annelid organization extant, M. de 

 Ouatrefages, thus concludes his elaborate memoir on the nervous 

 system of the annelida : — 



" We must then seek elsewhere (than in the nervous system) the 

 characteristics on which to base the divisions which are necessitated 

 by the great extent of this group, and the multiplicity of types which 

 it embraces. Now, as an anatomical character, there is nothing more 

 distinct and well marked than the union or separation of the sexes in 

 the same individual. These differences of organization, besides, 

 indicate profound physiological distinctions, which have long been 

 justly appreciated by botanists. I am, therefore, more and more 

 inclined to believe that the distinction of the annelids (Vers) into 

 moncecious and dioecious ought to be adopted in science." ^ 



In arriving at this conclusion, M. de Quatrefages was, of course, 



^ On consulting the original description of Filograna — a genus to which the form of the 

 Vermidom of this species would at first induce one to refer it, its affinities therewith appear 

 evident ; but whether there is any real difference between Filograna and Protula is a question 

 for further consideration. 



^ See among other authorities, Frey and Leuckart, op. cit. inf., p. 87, who examined 

 Hermella, Vermilia, Fabricia, and Spirorbis, among the tubicolar annelids, with especial 

 reference to this point. 



^ Types inferieurs de I'Embranchement des Anneles. Ann. des Sc. Nat. 1850. 



