an some Chatopod Annelids. 331 



wider inquiry as to its true nature ; that the two forms of fission 

 already knowTi as " parting " and " budding " both occur in the 

 Naids, and occur so as to prove their morphologic and physio- 

 logic identity ; that " parting " appears to characterize the Naids 

 with a prolonged upper lip (the genus Stylaria), while "budding^' 

 appears to characterize those with a short one (Nais, Dero, 

 Enchytrceus, and CJuEtogaster, according to Claus) j that the bud 

 produced by both these processes is identical with the parent ; 

 that as the buds are here, so far as I know, identical with their 

 parents in function and structure, there is no metagenetic fission; 

 and that therefore fission in these Naids, whether by " parting^' 

 or by " budding," is correlative to genesis in the great function 

 of maintenance of the species, and not a mere step in the history 

 of the individual*. 



It may be worth while to refer briefly here to the power of 

 reproduction from injuries commonly attributed to these little 

 beings, especially as Dr. Williams, in his " Report on the British 

 Annehda " (Rep. Brit. Ass. Adv. Sc. 1851, p. 247), after quoting 

 a summary of Bonnet's well-known experiments, says, " On the 

 authority of hundreds of observations laboriously repeated at 

 every season, the author of this report can declare with deliberate 

 firmness that there is not one word of truth in the above state- 

 ment/' It may be presumed from this, that Dr. Williams felt 

 the necessity of thorough and very careful investigations before 

 contradicting the statements so often repeated upon this subject ; 

 and I cannot doubt that his experiments have uniformly failed. 

 But, from the almost uniform success of my own, I should won- 

 der that they have done so, had not others reported complete or 



* " From the analogy of the two species {Arenicola and Nais) on which 

 the author's ohservations have been chiefly conducted, the conclusion may 

 be deduced that the ' fission of the body,' in every other species of Anne- 

 lida in which it occurs, has for object in like manner to protect and incu- 

 bate the ova.". ..." It becomes the last act of the parental worm, since 

 the portions into which the body is subdivided by fission never take food." 

 . ..." It is a catastrophe in which every autumn involves the whole com- 

 munity." (Williams, Rep. Brit, Annel. pp. 249, 250.) 



I should be far from wishing to extend the conclusions I have made to 

 all other Annelids by mere analogy ; but my observations are, at |least, 

 wholly incompatible with a general application of Dr. Williams's state- 

 ments to the Naids. 



The exact circle of life and its duration I have not determined, nor do I 

 feel certain that any of the general statements (see Leidy, ' Flora and Faima 

 within Living Animals,' 'On Stylaria fossularis,' and Williams at large) 

 are absolutely correct ; for I have known the process of fission to go on in 

 winter, when the Naids were kept in a warm place, while I have also seen 

 what appeared to be a loss of this power, as shown in badly formed and 

 incomplete buds occurring in the warmer parts of the year. 



22* 



