ENTOMOLOGY MYRIAPODA. 409 



differ from them entirely iu their mode of growth and development. The 

 Myriapoda acquire a periodical addition of segments and legs, with their 

 separate ganglia, nerves, and other structures. This addition of new parts 

 at each change of tegument takes place in all the Myriapoda up to a certain 

 period of their growth, which period varies in different genera. But this 

 addition of parts never occurs in insects, even in the lowest forms of the 

 class, or even in their earliest stages, after leaving the ovum." 



The author enters yet more fully into these considerations, and if in cer- 

 tain points he has gone too far, as in denying the after formation of legs 

 in insects, which is a necessary condition where the larvae are destitute 

 of them, still the comparison on the whole is convincing. He then goes on 

 to controvert the high authority of Brandt, regarding, as Leach and Latreille 

 have done, the Myriapoda as a distinct class. It is a step gained in this 

 inquiry that the author attaches importance to the mode of development ; 

 and if he had not at the outset dismissed from his mind the comparison 

 between Myriapoda and Crustacea (among which he probably had in view 

 the Crayfish alone, as is often the case), it is likely he would have clearly 

 perceived their close agreement. In the arrangement of the Myriapoda 

 Newport has in general followed Brandt, except that he has come nearer to 

 nature by breaking up the sub-order Siphouizantia of the latter. A. number 

 of new genera are proposed by him, particularly among the Scolopeudrse, 

 which has made the more precise determination of the older genera neces- 

 sary. To render this summary complete I insert the Synopsis geuerum, as 

 he has given it. 



[As this has been given also in the Annals of Natural History (xiv, 50-53), 

 it seems unnecessary to transcribe it here.] 



In continuation, the external structure of the Myriapoda is described. 

 Newport regards each separate segment as consisting of two subordinate 

 segments, of which one only (the hinder) comes to perfection in the Chilo- 

 poda, while in the Chilognatha the ventral plates at least of both are 

 developed in an equal degree, each bearing a pair of legs. The completely 

 erroneous explanation of the parts of the head, applied to the Chilopoda, is 

 surprising in so judicious and penetrating an anatomist. He considers the 

 large pair of pincers as the mandibles, which obliges him to treat the seg- 

 ment on which they are seated as a portion of the head, " basilar segment," 

 while the true head is denominated "cephalic segment." As a natural con- 

 sequence, the structure of the mouth is misunderstood. The mandibles are 

 designated maxillae, the maxillae maxillary palpi, the third pair of jaws tongue, 

 the first pair of legs labial palpi. The parts which he takes for the man- 

 dibles are the first pair of legs, his basilar segment is the mesothorax. (See 

 Erichson's Entomographien.) The side view of the fore part of a very young 

 Geophilus, which Newport has given in fig. 3, is particularly instructive. 



