from Chilu Il!5 



been suffered to die unheeded, that the contracting muscles have 

 become sufficiently relaxed to allow them to be put into a natural 

 position without injury to the shell, or separating the valves, but 

 this is too uncertain ah occurrence to be depended on. The ani- 

 mal, being dead, is to be extracted from the shell with a sharp 

 pointed knife, beginning at the posterior part, and cutting round 

 on both sides towards the head. J advise this mode of proceeding 

 from the internal structure of the valves being less liable to injury 

 than by cutting promiscuously from head to tail, in which case the 

 knife would cut against the sharp edges of the valves, and cause 

 much damage to them ; but in the former method of operating the 

 knife only passes over them in the direction in which they lie, 

 consequently not with so much danger of detriment to the shell as 

 the other. After cleansing the shell it should be laid on a flat 

 board, with the margin spread in the same manner in which it was 

 observed to be before the specimen was taken, and to prevent the 

 ends of the shells being brought towards one another by the con- 

 traction of the muscles in drying, another flat board should be 

 placed over them, with a weight proportionate to the size of the 

 shells ; they should be allowed to dry very gradually, and it will 

 be necessary to pay some little attention to them while drying, in 

 order that the edges of the margins may not become shrivelled up 

 by drying sooner than the other part. 



Following the example of the writer of the interesting paper on 

 the British Chitones, which appeared in the 5th number of this 

 work, I have divided the genus into sections, corresponding with 

 the character of the margin, the propriety of which arrangement 

 appears to be too evident to meet with any opposition. 



It is perhaps worthy of remark, that out of more than 500 spe- 

 cimens, not one occurred with only seven perfect valves ; but in a 

 few instances I have found them with one of the valves imperfectly 

 formed, which, on a slight inspection, might be overlooked, being 

 nearly, or wholly, covered by its neighbours. These malfor- 

 mations, I have no doubt in my own mind, proceed from accident 

 during the early period of the animal's existence. It may be 

 answered that these, as well as others of this class, have the power 

 of replacing any injury they may receive in their covering during 



X 2 



