140 



VERMES 



FHTLUM III 



described by Hinde in the Ordovician, Silurian, Devonian and Carboniferous 

 rocks of the United States, Canada, Great Britain and Sweden (Island of Got- 

 land). These are very small, black, highly lustrous bodies, extremely variable 



in form (Fig. 222), and mainly 

 composed of chitinous material 

 which is unaffected by acid. They 

 exhibit a striking resemblance to 

 the jaws of recent Annelids, and 

 probably represent a large number 

 of genera. 



Of less certain derivation are 

 the microscopic teeth first described 

 by Pander under the name of 

 " Conodonts " (Fig. 223), which 

 occur detached in the Cambrian 

 (Blue Clay underlying the Ungulite 

 Grit) of St. Petersburg, and are 

 also very abundant in beds of 

 Ordovician, Silurian and Car- 

 boniferous age in Russia, Great 

 Britain, the United States and 

 Canada. They are usually translucent, lustrous or corneous, and are composed 



Fig. 221. 



Lumhricaria colon Miinst. Lithograi)hic Stone 

 hofen, Bavaria. Natural size. 



Solen- 



B 



D 



Fk;. 222. 



Paleozoic Annelid-jaws. A, Lnmhriconereiteshasalis Hinde. Silurian ; Dundas, Ontario, lo/j. B, Oenonitcf: 

 rostrahis Hinde. Toronto, i^/j. (', Etinicites varimis Grinnell. Toronto. B/j. X), Araheliltes scutellutus 

 Hinde. Ordovician ; Toronto. I'Vi- 



of carbonate and phosphate of lime. They exhibit verj^ great variety in form. 

 By Pander and others these fossils have been regarded as fish-teeth. Zittel 



Fio. 223. 



Conodonts, greatly enlarged. A, B, J'altudus truncatiis Pander (after Pander). C, Prioniodus elcgans Pander. 

 Cambrian ; St. Peter.sburg. D, Polygnathus duhiua Hinde. Devonian ; North Evans, New York. 20/j. 



and Rohon, however, consider that they are Annelid jaws, but their tiue 

 position cannot yet be said to have been positively determined. 



