316 CRITIQUES AND ADDRESSES. [xn. 



Professor Haeckel adduces the fossil Crossopodia and 

 Phyllodocites as examples of the Annelidan forms, by 

 the coalescence of which the Echinoderms may have 

 been produced ; but, even supposing the resemblance 

 of these worms to detached starfish arms to be perfect, 

 it is possible that they may be the extreme term, and 

 not the commencement, of Echinoderm development. 

 A pentacrinoid Echinoderm, with a complete jointed 

 stalk, is developed within the larva of Antedon. Is 

 it not possible that the larva of Crossopodia may 

 have developed a vermiform Echinoderm ? 



With respect to the Phylogeny of the Arthropoda, I 

 find myself disposed to take a somewhat different view 

 from that of Professor Haeckel. He assumes that the 

 primary stock of the whole group was a crustacean, 

 having that Nauplius-form in which Fritz Miiller has 

 shown that so many Crustacea commence their lives. 

 All the Entomostraca arose by the modification of some 

 one or other of these Naupliform " Archicarida." 

 Other Archicarida underwent a further metamorphosis 

 into a Zocea-foxm. From some of these " Zoeopoda " 

 arose all the remaining Malacostracous Crustacea ; 

 while, from others, was developed some form analogous 

 to the existing Galeodes, out of which proceeded, by 

 gradual differentiation, all the Myriapoda, Arachnida, 

 and Insecta. 



I should be disposed to interpret the facts of the 

 embryological history and of the anatomy of the Arthro- 

 poda in a different manner. The Copepoda, the Ostra- 

 coda, and the JSranchiopoda are the Crustacea which 

 have departed least from the embryoDic or Nauplius- 

 forms ; and, of these, I imagine that the Copepoda 

 represent the hypothetical Archicarida most closely. 

 Apus and Sapphirina indicate the relations of these 

 Archaeocarids with the Trilobita, and the Eurypterida 



