LITERATURE. 257 



logically as the older, and the Chilopoda as the younger forms, it 

 only remains to be said that the latter also became separated from 

 the racial form early, and each branch, developing further inde- 

 pendently, while retaining ancient features, acquired characters 

 which, in consequence of their separate development, were not the 

 same in the two groups. 



The most important feature in the organisation of the Myriopoda 

 is the uniform development of the trunk-segments and the possession 

 of limbs on all or nearly all these segments. This feature gives 

 the Myriopoda a specially primitive character, and brings them near 

 to those other forms which show a homonomous segmentation of 

 the body, viz., Peripatus and the Annelida. 



[In the above account the Myriopoda are treated as a natural group, and as 

 such they are probably regarded by the majority of zoologists. This, however, 

 is not the opinion of those who have specialised in this group, and a separation 

 of the Diplopoda from the Chilopoda was suggested as early as 1887 by Pocock, 

 a view which he afterwards amplified (No. VI.). Pocock regards the Chilopoda 

 with the Symphyla as much more nearly related to the Hexapoda than to the 

 Diplopoda with the Pauropoda, and he proposes to divide the Tracheata into 

 two groups— (1) the Opisthogoneata, including the Hexapoda, Chilopoda, and 

 Symphyla ; and (2) the Progoneata, embracing the Diplopoda and the Pauro- 

 poda, the latter, according to Kexyox, being modified Diplopods. He regards 

 the Symphyla as standing nearest the ancestral form of the whole group. 

 Precisely similar conclusions have been arrived at by Silvestri (No. IX.), 

 who also has made a special study of the Myriopoda. These views have been 

 accepted by Ray Lankester (No. V.) and others. Kingsley (No. IV.), while 

 agreeing that the Myriopoda form a purely artificial group and that the Chilopoda 

 are closely related to the Hexapoda, differs from Pocock in concluding that 

 the Diplopoda have probably no relation at all to the Chilopoda. The view 

 that these two subdivisions of the Myriopoda are quite distinct from one 

 another, or at the most but slightly related, is amply confirmed by the study 

 of their ontogeny, as may be seen from the numerous points of difference 

 mentioned above. — Ed.] 



LITERATURE. 



1. Bode, J. Polyxenus lagurus. Ein Beitrag zur Anatomie, 



Morphologie u. Entwicklungsgeschichte der Chilognathen. 

 Zeitschr. f. d. ges. Naturwiss. Bd. xlix. Halle, 1877. 



2. Eisig, H. Die Capitelliden. Monographie der Fauna, u. Flora 



des Gol/es von Neapel. xvi. Berlin, 1887. 



3. Fabre, L. Becherches sur l'anatomie des organes reproduc- 



teurs et sur le developpement des Myriopodes. Ann. Sci. 

 Nat. (4). Tom. iii. Paris, 1855. 



4. Grenacher, H. Ueber die Augen einiger Myriapoden. Archiv. 



f. Mih-o. Anat. Bd. xviii. 1880. 



5. Haase, E. Beitrag zur Ontogenie u. Phylogenie der Chilopoden. 



Zeitschr. f. Entomologie. N. F. Heft viii. Breslau, 1881. 



s 



