146 Linncean Society. 



to endeavour to apply them to the explanation of function as de- 

 pendent on structure. 



Although the object of variations in structure cannot always be 

 at once traced in the details, it is invariably evident in the general 

 design of parts, and it is found to be so likewise in their peculiarities 

 in proportion as we become more fully acquainted with the habits of 

 animals, as is shown in the details of structure in the young Meloe 

 and Stylops at particular periods of their growth. Changes in the 

 structure of parts during growth in the young animal were shown to 

 commence in the cells of the tegument, and that it is by means of 

 these that the form of the body is gradually altered. These changes 

 are not to be confounded with other secondary ones which give form 

 to the adult animal, and which we are familiar with as the meta- 

 morphoses. 



The dermal appendages, spines, hairs and scales, were shown to 

 be similar in their mode of origin in the tegument to the appendages 

 of segments, and their growth and removal to be regulated by the 

 same principles. Mr. Newport showed that the appendages originate 

 by an extension outwards of the whole of the layers of a portion of 

 tegument, whilst spines, hairs and scales originate in the nuclei of 

 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 view 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 Articulata, during 

 their growth and enlargement, by involving contiguous portions of 

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

 gument of Meloe, 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 



