216 RAMBLES OF A NATURALIST. 



decidedly the most unsuccessful ; for during the 

 whole time of our sojourn at Santo-Yito, I did not 

 see a single phlebenterous mollusc, whilst even the 

 annelids were of rare occurrence. I had, however, 

 the opportunity of devoting my attention to a genus 

 belonging to this group, and although I did not 

 complete my observations until a later period, I was 

 enabled to lay before my companions the curious 

 facts which I had discovered on the coasts of the 

 Channel during my stay at Brehat, in reference to 

 the mode of propagation of the Syllis. 



It was formerly believed, in accordance with the 

 observations of the old Danish zoologist, Miiller, 

 that these little errant annelids, which are only from 

 two to three inches long, v^erejissiparoiis; that is to 

 say, that one individual being first single and entire, 

 could separate into two halves, each of which ac- 

 quiring rapidly either a head or a tail, became a 

 perfect animal, destined to live precisely in the same 

 manner as the oriojinal beino; from which it had 

 sprung. This mode of generation, which is common 

 enough in simple animals, was very remarkable in 

 the case of the genus Syllis, in which the organi- 

 sation is of a somewhat complicated kind. It must 

 be remembered, however, that very different con- 

 ditions prevail among the animals of this genus. 



When a Syllis is about to reproduce itself, a 

 number of rings become developed at its posterior 

 extremity, the first ring being soon organised into a 

 head, provided with eyes and antennae. The two 

 annelids, parent and offspring, continue, however, 

 to be united by the skin and the intestine, in such a 



