64 KTIRNNK GEOFFROY SAINT-HILAIRE 



of the thorax, the abdomen, and the terminal segment of the 

 abdomen (p. 455). ' 



The skeleton of the insect's head is said to correspond to 

 the bones of the face, to the bones of the cerebrum and to the 

 hyoid of higher Vertebrates, the skeleton of the prothorax to 

 the bones of the cerebellum, of the palate, and the pieces of 

 the larynx, the skeleton of the mesothcrax to the parietals, 

 interparietals, and opercular bones, and that of the meta- 

 thorax to the skeleton of the thorax of Vertebrates. The 

 pieces of the abdomen and of the terminal segment 

 correspond to the bones of the abdomen and coccyx 

 (p. 458). It does not need the subsequent likening of the 

 hind wings of insects to the air bladder of fish, and of the 

 stigmata to the pores of the lateral line, to convince one 

 finally of the fancifulness of the whole comparison. 



In 1830 two young naturalists, Meyranx and Laurencet, 

 presented to the Academic des Sciences a memoir in which 

 they likened a Cephalopod to a Vertebrate bent back at the 

 level of the umbilicus, saying that the Vertebrate in this 

 position had all its organs in the same order as in the 

 Cephalopod. Geoffrey took up this idea with enthusiasm, 

 seeing in it a ' further application of his master-idea of 

 the unity of plan and composition. By means of this 

 comparison Mollusca definitely took their place in the l-.cJicllc 

 dcs cfrcs, after the Articulata, just as Gcoffroy had maintained 

 in 1820, saying that crabs formed a link between the other 

 Crustacea and the molluscs. 1 The comparison brought him 

 nearer to the end he had in view, the reference of all animal 

 structure to one single type. 



But in championing the memoir of Meyranx and 

 Laurencet, Geoffrey found himself in direct antagonism 

 with Cuvier, who held that his four " Embranchements " had 

 each a separate and distinct plan of structure. In a paper 

 read to the Academy in February 1830,- Cuvier easily 

 demolished the crude comparison of the Cephalopod to the 

 Vertebrate, lie gave diagrams of the internal organs of a 

 Ccphalopod and of a Vertebrate bent back in the manner 

 indicated by Meyranx and Laurencet, and he showed in 



1 /si's, p. 549. 



: I'ulilislic.l in Ann. Sci. AW/., xix., |>p. 241-59, 1830. 



