SECT, xv CLASSIFICATION OF CRUSTACEA 253 



Eurypteridae, and Phyllopoda, there occur numerous 

 remains of Ostracoda and Cirripedia. If we can 

 in any way connect these latter with the above 

 named, we shall have solved the difficulty expressed 

 by Barrande and felt by many, that the Crustacea first 

 appear in the geological record in several widely dif- 

 ferent groups, almost simultaneously, and without any 

 transition forms either leading up to them or linking 

 them together. Our derivation of the former groups 

 from bent Annelids with no hard chitinous skeleton 

 which could have been preserved, explains the 

 sudden appearance of these groups. We have still 

 then to show that both the Ostracoda and the 

 Cirripedia are deducible from these forms. As, how- 

 ever, these two groups have modern representatives, 

 we shall treat them in order among the other living 

 forms. 



We have then to ask the question, From which of 

 these primitive Crustacean forms did the modern 

 Crustacea arise ? For some groups, fortunately, 

 the answer is clear ; as to others, however, we can 

 only guess. 



The attempt which we here make to sketch out a 

 new classification of the Crustacea must be understood 

 to be quite provisional. In establishing the bent 

 Annelid as the origin of the Crustacea, we have done 

 nothing more than lay the foundation stone for the 

 construction of a complete and final classification of 

 the Crustacea, including, for the first time, the hitherto 

 enigmatical palaeozoic forms. It is, however, as 

 completely out of the sphere of this book as it is 



