1 1 6 Mr Thomas A. Huxley on a Hermaphrodite and 



there is therefore, perhaps, nothing so very anomalous in the 

 discovery of a truly hermaphrodite tubicolar annelid. It is 

 another question how far it need affect the classification to 

 which I have alluded. 



The fluctuation in the terminology of the classification of 

 the annelids, in fact, has proceeded from the very common but 

 always obstructive practice of giving notional instead of trivial 

 names to incomplete groups of animals. Cuvier divided the 

 annelids into errant, tubicolar, terricolar, &c, deriving his 

 terminology from the habits of those with which naturalists 

 were then acquainted ; but, with the advance of knowledge, it 

 was found that some of the Errantia inhabit tubes, while 

 one main division of the " Terricola " consists of aquatic 

 worms ; and thus these notional terms, instead of aiding the 

 memory as they were intended to do, served simply to origi- 

 nate and propagate erroneous conceptions. There can be no 

 doubt that the divisions established by Cuvier are essen- 

 tially natural, and had he devised some happily unintelligible 

 Grecism, instead of the names which he actually adopted, they 

 would have stood, their definitions altering with the progress 

 of knowledge, until this day. 



The divisions proposed by M. Milne-Edwards possess exactly 

 the qualification which is here wanting. Annelides and Sco- 

 Uides may mean anything, and, as names of groups, may very 

 conveniently remain, even if it should be found necessary to 

 remodel the whole definition which was primarily assigned to 

 them. It appears to me, therefore, that if the statements which 

 follow be confirmed, they will lead, not to an alteration or sub- 

 division of the group of Annelides, but to a widening of its de- 

 finition so as to include hermaphrodite forms; or perhaps it would 

 be better to admit that owing to the imperfection of our know- 

 ledge, we have not yet a definition of either Annelides or 

 Scoleides at all, but that we must arrange under the former 

 head all those worms which resemble the errant and tubicolar 

 sea worms more than anything else, while those which resemble 

 the land and fresh water worms must fall under the latter cate- 

 gory. If, from the great division of the Annulosa, we take 

 away those animals which are characterized by the possession 

 of one or more of the following characters — 1. Articulated 



