CHAPTER VII. 



CLASS III. MYRIAPODA.* 



Tracheates with numerous and similar pedigerous segments, 

 with one pair of antennae followed by a pair of palpless mandibles, 

 with regularly and segmentally arranged tracheal stigmata, and 

 with malpighian tubules. The young are, with a few exceptions, 

 not provided with the full complement of segments at hatching. 



Very few of the characters mentioned in the definition are 

 peculiar to Myriapoda ; they are almost all found in Insecta or 

 Onychophora. This fact coupled with the great variation of 

 structure found in the group points to the conclusion that the 

 classes Insecta, Onychophora and Myriapoda are the survival 

 of a once great and continuous group of land Arthropods, a 

 large number of which have become extinct, leaving two groups, 

 Insecta and Onychophora, each fairly compact and showing 

 but little variety of organization, and one, the Myriapoda, loose 

 and heterogeneous with considerable gaps between the orders. 

 In fact it might fairly be held, and has indeed been maintained, 

 that the line of cleavage between the opisthogoneate and pro- 

 goneate Myriapoda is sufficiently distinct to justify the aban- 

 donment of the class and the substitution in its place of two 

 classes, the Opisthogoneata including the Chilopoda, and the 

 Progoneata with the Chilognatha, Pauropoda, and Symphyla 

 as orders. Of these two classes the Progoneata have special 

 features of their own, e.g. the position of the genital opening 



* J. F. Brandt, Recueil des memoires relatifs a Vordre des Insectes Myria- 

 podes, Petersbourg, 1841. G. Newport, On the nervous and circulatory 

 systems of Myriapoda and Macrourous Arachnida, Phil. Trans. 1843. 

 M. Fabre, Recherches sur 1'anatomie des organes reproducteurs et sur le 

 developpement des Myriapodes, Ann. Sci. Nat. 1855. C. L. Koch, Die 

 Myriapoden, 2 Bde, Halle, 1863. H. Grenacher, Ueber die Augen einiger 

 Myriapoden, Arch. /. Mikr. Anat., 18, 1880. R. Latzel, Die Myriopoden 

 der osterreichisch-ungarischen Monarchic, 1 and 2, Wien, 1880, 1884. A. 

 Kowalewsky, Etude des glandes lymphatiques de quelques Myriapodes, 

 Arch. Zool. Exper., 1896. Also E. Ray Lankester, R. Heymons, op. cit. 

 on p. 314. 



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