1848.] Linnean Society. 369 



cells of separate layers. He stated also that he had detected these 

 modes of origin in the embryo before it leaves the ovum, and com- 

 bated the vievi^ of M. Lavalle that spines are originally an extension 

 outwards of the whole of the dermal tissue, as they are often found 

 to be in Crustacea at advanced periods of growth, showing that they 

 only become so in them, and in the larvae of other Artimlata, during 

 their growth and enlargement, by involving contiguous portions of 

 the tissue. These views were illustrated by examination of the te- 

 gument of Melbe, and by reference to the changes in the tegument of 

 Lepidoptera at the period of transformation. 



The author then passed to a consideration of the secondary causes 

 of development — the metamorphoses — and pointed out, from an ex- 

 amination of the cast skin of the larva of Meloe, which always 

 remains attached to the body of the inactive full-grown larva in its 

 cell, what are its previous habits and form, drawing attention to 

 the fact, that the cast skin of an insect, when relaxed and unfolded, 

 enables the anatomist of the Invertebrata to indicate the form and 

 general habits of a species as precisely as the fossil bone enables the 

 comparative anatomist of the Vertebrata to indicate those of the in- 

 habitant of a former world. 



The changes which Meloe undergoes were then described ; and 

 the mode of formation of the head in the Articulata explained as 

 composed of a definite number of originally distinct segments. 

 Mr. Newport referred to his former discovery of these segments in 

 the embryo of Geophilus, and stated, in answer to the recent denial 

 of some parts of his views by Professor Erichson, regarding the 

 organs of manducation in Myriapoda, that he has satisfied himself of 

 their correctness, having not only confirmed them in that class, but 

 also in the embryos of other Articulata. These views he then ap- 

 plied to illustrate the anatomy of the head and organs of manducation 

 in Meloe, showing the mode in which the changes in the structure 

 of the mandibles are effected, and pointing out corresponding changes 

 in the function of the parts ; noticing also that change in structure 

 during the growth of an animal usually precedes change in the 

 function of an organ, — a circumstance which leads to the inference 

 that function is closely dependent on special structure. 



The secondary changes during the development of Articulata, the 

 metamorphoses, are effected, not by the tegument itself, but by the 

 agency of structures connected with the tegument — the muscles. The 

 author stated that we are entirely ignorant of the secret cause which 

 first excites the muscles, at a definite period of growth, into action 

 in effecting these changes ; but suggested that it is in the expansive 



