114 Mr Thomas A. Huxley on a Hermaphrodite and 



composed of very fine, more or less undulated, white, calca- 

 reous tubes, attached by one end to some solid body. Rising 

 from this fixed base, they unite together side by side into 

 irregular bundles, and these bundles anastomose like bundles 

 of nerves in their plexuses — leaving irregular spaces here and 

 there, and thus forming a kind of coarse solid network (fig. 1). 

 Each tube has a circular section, but can hardly be called 

 cylindrical, because it is thickened at intervals, so as to be 

 obscurely annulated. 



When placed in a vessel of clear sea-water, the annelids 

 issue from the tubules of their vermidom, and each spreading 

 out its eight branchial filaments and displaying its bright 

 red cephalic extremity — the mass assumes a very beautiful 

 and striking appearance — singularly resembling a tubulipa- 

 rous polyzoarium (fig. 2). 



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 oper- 

 culum, would point at once to the genus Protula* as that to 

 which this species belongs, were it not for two most remark- 

 able 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 

 undergoes Jissiparous multiplication ; and, in the second, that 

 it is hermaphrodite — the male and female reproductive ele- 

 ments being, unequivocally, developed in the same individual. 



So far as I am aware, the process of fissiparous multiplica- 

 tion has hitherto been observed in only one family among 

 the errant annelids, the Syllidea (of Grube) ; in only one 

 family among the Scoleidm(Hirudinido3m&Lumbricido3),t\i&t 

 of the Naidea, — and in only one genus among the tubicolar 

 annelids, Filograna. 



* 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 jhere is any real difference 

 between Filograna and Protula is a question for further consideration. 



