CLASS I 



CHAETOPODA 



139 



Serpulites Mnrdh. Very long, smooth, compressed, and somewhat bent 

 calcareous tubes, the layers admixed with organic substance. Ordovician and 

 Silurian. 



CornuUtes Schloth. Thick-walled, trumpet-shaped tubes, Serpula-like at the 

 lower end, and sometimes attaining a length of three or four inches. Exterior 

 annulated, and covered with very -fine longitudinal Striae. Some authors 

 regard the tubes as Pteropod shells. Ordovician to Devonian. 



Ortonia Nich. Small, conical, slightly flexuous, thick-walled calcareous 

 tubes, cemented by the whole of one surface to some foreign body. Sides of 

 the tube ringed with imbricating annulations, the free upper surface apparently 

 cellular in structure. Ordovician to Carboni- 

 ferous. 



Conchicolites Nich. Conical, slightly bent, 

 thin-walled tubes, growing together in Clusters, 

 and attached by the small lower ends to 

 orthoceratite or Brachiopod shells. Tubes 

 made up of numerous short rings, each of 

 which partially overlaps the subjacent one. 

 Ordovician. 



The peculiar group Myzostomidae, which 

 are external parasites on Kecent Crinoids, are 

 thought to be related to the Chaetopoda. 

 Graff has shown that they also infested the 

 column Segments of Jurassic Crinoids. 



Order 3. ERRANTIA. (Nereidae). 



Free - swimming, predaceous Polychaeta, with 

 well-marJced liead. Proboscis capoMe of protrusion, 

 and armed with papillae or powerful jaws. Para- 

 podia 7nuch more developed than in the Tubicola, 

 heset with setae, and serving for locomotion. 



Undoubted remains of Errant Worms have 

 long been known from the Lithographie Stone 

 (Upper Jura) of Bavaria, and include the 

 trails, calcified jaws and excrements of num- 

 erous species. The principal genus from this 

 horizon is Eunicites Ehlers {Geophilus Germar) 

 (Fig. 220), perfect impressions of which are 

 also found in the Upper Eocene limestone of 

 Monte Bolca, Italy. Archarenicola Horwood 

 is known from the English Rhaetic. 



Uiider the designation of Lumhricaria 

 Münster (Lumbricites Schlotheim) (Fig. 221) 



are included a variety of obscure. remains from the Lithographie Srone, 

 which may be best regarded as the excrements of Annelids. They occur 

 as irregularly contorted bands or strings, sometimes in the form of very 

 long labyrinthic coils. 



Of peculiar interest are the minute detached jaws and denticulated plates 



Fig. 220. 



Eunicites avitus Ehlers. Lithographie 

 Stone ; Eichstädt, Bavaria. Natural size. 



