VERTICAL UANiJK oK Till: Ai:.\< HNIDA ;M 



TABLE SHOWING THE VERTICAL RANCK <>F Till: A i;.\CII \ II > \ ! 



SUB-PHYLUM B. MYRIOPODA. 



Tracheate Arthropods with distinctly separated head and numerous fairly similar 

 segments, each of which bears one or two pairs of legs. Body vermicular, apterous. 

 Head with one pair of antennae and three pairs of jaws. 



The head in Myriopods is formed by a single division, which only in exception,! 1 



cases is supplemented by parts of the following body segments. The two most 



important orders are Chilopoda and Diplopoda. In the former, which approaches very 



closely to Insects, every body segment possesses a single dorsal and a ventral plate, to 



which a pair of legs is attached. The 



Diplopods, on the other hand, show on every 



segment except the first a dorsal plate and 



two ventral plates, with two pairs of legs. 

 A precursor of the Chilopods is found 



in the genus Palaeocampa, M. and \V., from 



the Carboniferous, whose body is composed 



of but a, few segments. Scudder place.s it 



in a distinct order, Protosyngnatha. True 



Chilopod genera (Germatia, Kossi ; Scolopendra, Linn. ; Lithobius, Geophilm, Leach) 



ocGiir in anilx-r and the fiv.<h- water gypsum !' 

 Aix, Provence. 



Most Palaeozoic Myriopods are of large size 

 and belong to the order Archipolypoda, in which 

 all body segments possess two dorsal and two 

 ventral plates, with two pairs of legs. Two 

 genera are found in tin- old Red Sandstone of 

 Scotland, Archidesmus, Peach (Fig. 1438) ; and 

 Kampecaris, Page. Numerous others occur in 

 the Carboniferous and Trias of both continents, 

 and sonic have l>ccn recognised by Matthew in 

 the Devonian of New Brunswick. Kzamples : 



Euphoberia, M. and W. (Fig. 1439); Amynilispes, Scudder; Xylobim, D<iwson ; 



Acantherpestes, M. and W., a genus regarded by Scudder as probably amphibious. 

 From Mesozoic rocks but a single species is known (Jiilnpniit 



Ki... . 



Ar<-hi>i- rh. Devon:.-; 



. Scotland. 1/1 (after IVarlu. 



Fiii. 1439. 



Euphoberfo, armigera, Meek ami W. 

 Measures ; Maxon Creek, Illinois. 1/1- 



Coal 



1 The figures indicate the number of species, as estimated in 1885. 



