DESCRIPTIONS OF GENERA AND SPECIES. 



Myi'iapoda from the Tertiary rocks are almost unknown, a single species 

 a little larger than ours having been figured by Bertkau from Eott under 

 the name of lulus antiquus Heydeii. Other species have been indicated. 

 Serres, for instance, speaks of one found near Montpellier, allied to the living 

 I. sabulosus, and this mention has been quoted by Meyer, Keferstein, and 

 Geinitz. Hope also catalogues one from Aix, and Cotta mentions one, per- 

 haps I. terrestris, from Tharand, Saxony, which is probably a recent 

 inclosure, and is quoted by Brulld and Berendt. Besides these diplopods 

 Hope catalogues a Scolopendra from Aix, and Keferstein, on the authority of 

 Aldrovandi, mentions a Scolopendra from Glarus, in Switzerland. 



Tlie Baltic amber, however, contains a considerable number of species, 

 twenty di]jlopods having been recorded and most of them described, belong- 

 ing to the genera Craspedosoma (seven species), Polyxenus (five species), 

 lulus (four species), and Euzonus, Lophonotus, Blaniulus, and Polydesmus 

 (one species each). The chilopods have a less number of species, fifteen, 

 representing the genera Lithobius (eight species), Geophilus (three species), 

 and Cermatia and Scolopendra (two species each). All these genera 

 excepting Euzonus are represented among living forms. 



The single species found in America belongs to the diplopods. (No- 

 vember, 1881.) 



Order IDIPLOPOID^ Gervais. 



Family lULlD^E Leach. 



As in the case of the Rott species described by Bertkau, the form 

 described below is only referred to the genus lulus in a broad sense, its 

 preservation being very defective. It is smaller than the European species. 



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