SECT. I OBJECT AND LINE OF ARGUMENT 5 



pharynx unnecessary, so that it degenerated. The 

 Annehds afford us such a wonderful variety of 

 forms adapted to almost every possible manner 

 of life, that this assumption presents no difficulty. 

 Cambrian and Silurian formations have revealed to 

 the palaeontologist abundant evidence that early 

 Chaetopods crawled about along the bottom of the 

 seas of those times. That one of these should become 

 specialised for feeding in the manner supposed, is 

 not too much to ask. 



The use of the pharynx just described is, as far as 

 we can see, a clumsy method of obtaining food. The 

 loss of it, and the adoption of a browsing method of 

 feeding, might well be a gain. The further develop- 

 ment of this habit would lead to a bending round of 

 the head sufficient to enable the animal to use its 

 anterior parapodia for pushing prey into its mouth. 

 In time the bend of the head would become fixed, and 

 the parapodia modified as jaws and maxillae. The 

 parapodia of at least a certain number of anterior 

 trunk segments would certainly also serve to rake 

 food together into the middle line and forward it 

 towards the mouth. From this very simple and natural 

 modification of a Ch^etopodan Annelid, we believe that 

 all the Crustacea, living or extinct, can be deduced. 

 To establish this, is the object of this little book, which 

 we have called " The Apodidae," since it was during our 

 study of these Phyllopods that we first caught sight of 

 the Annelid, so effectually disguised under its Crusta- 

 cean dress. Although this disguise is so complete as to 

 have eluded all former research, yet when once under- 



