SUB-ORDER B 



VERMES 



Of peculiar interest are the minute detached jaws and toothed plates dis- 

 covered by Hindu in the Ordovician, Silurian, Devonian, and Carboniferous 

 rocks of Canada, Great Britain, and Sweden (Island of Gottland). These are 



(Sf , 



Fia. 407. 



Palaeozoic Annrlidi'-.jiiws. A, Lnmbricmiereit<'sbas<ilis, Hinde. Silurian ; Dundas, Ontario. N>/I. n,0enonites 

 ,;>*(,< tut, Hinde. Toronto. A. C, Eunicites varians, Grinnell. Toronto. /!. D, ylra&eHites sciUellalu*, 

 Hiude. Ordovician ; Toronto. l/i. 



very small, black, highly lustrous bodies, extremely variable in form (Fig. 

 407), and mainly composed of chitinous material which is unaffected by acid. 



FIG. 408. 



..: Conodonts, highly magnified. A, B, Paltodvs truncatus, Pand. (after Pander). C, Prioniodus elegant, Pand. 

 Cambrian ; St. Petersburg. D, Polygnathus dubius, Hinde. Devonian ; North Evans, New York. 80/j. 



They exhibit a striking resemblance to the jaws of recent Annelides, and 

 probably represent a large number of genera. 



Of less certain derivation are the microscopic teeth so well described by 

 Pander under the name of 

 " Conodonts " (Fig. 408), which 

 occur detached in the Cambrian 

 (Blue Clay underlying the Un- 

 gulite Grit) of St. "Petersburg, 

 and are also very abundant in 

 beds of Ordovician, Silurian, 

 and Carboniferous age in 

 Russia, Great Britain, the 

 United States, and Canada. 

 They are usually translucent, 

 of a shiny, reddish horn-colour, 

 and are composed of carbonate 

 and phosphate of lime. They, 



too, exhibit great variety in FIQ- 409. 



form. By Pander and others y^rSfize"* 1 ' M<Leay> Cambrian : Liampeter, waic. 

 these fossils have been re- 

 garded as fish -teeth. Zittel and Rohon, however, consider that they are 

 Annelid jaws, but their true position cannot yet be said to be satisfactorily 

 determined. 



A quantity of supposed worm -borings, trails, impressions, and other 



