ON ANNELIDA, 75 



excavate their habitations to find in the detritus of the materials 

 which they swallow the substance which is to support them. 



We know very little concerning the mode of reproduction 

 in the majority of the chetopoda; it is in fact extremely diffi- 

 cult to make direct observations upon them in the bosom of 

 the waters, and often in the soil itself which they inhabit; and 

 it is not less difficult to institute experiments for the purpose 

 of ascertaining any information on the subject. 



We do not know whether all the species have need or not 

 of the approximation of two individuals to propagate their 

 species, as is certainly the case with the lumbrici. 



It is only certain, that towards the commencement of 

 spring, in our seas at least, we find the bodies of these 

 animals filled with eggs, or with a milky, and as it were sper- 

 matic matter. In South America, we know from Darfel, 

 quoted by Pallas, that the amphitrites at Cura9oa are in full 

 vigour in the months of September and October ; that at these 

 times they deposit their eggs, and that the young ones come 

 forth in the month of November. 



The number of the young is immense ; but are they de- 

 posited in the egg state or in that of the living animal, or in 

 particular localities ? These are facts of which we know 

 nothing, and we are likely very long to remain in such 

 ignorance. 



The species which live in tubes are certainly not bom with 

 one, as is always the case, on the contrary, with the conchy- 

 liferous mollusca, because with the latter the shell in reality 

 forms a part of their skin, which is not the case with the 

 tubicolous chetopods. It is then probable that the very young 

 chetopod has no tube, but that it forms one immediately 

 after it has been expelled from the bosom of the mother. 



We have still less information respecting the duration of 

 life in these animals ; we even know nothing in this respect 

 about the earth-worms, which we find in such abundance in 



