CLASS I 



CHAETOPODA 



139 



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

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

 Silurian. 



Cormdites 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 ujDper 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 Recent Crinoids, are 

 thought to be related to the Chaetopoda. 

 Graft' has shown that they also infested the 

 column segments of Jurassic Crinoids. 



Order 3. ERRANTIA. (Nereidae). 



Free- swimming, predaceoiis Polycliaeta, with 

 well-marked head. Proboscis capable of protrusion, 

 and armed with papillae or poiverfid jaws. Para- 

 podia rmich more developed than in the Tubicola, 

 beset with setae, and serving for locomotion. 



Undoubted remains of Errant Worms have 

 long been known from the Lithographic 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. 



Under the designation of Lumbricaria 

 Mlinster [Lumbricites Schlotheim) (Fig. 221) 



are included a variety of obscure remains from the Lithographic Stone, 

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

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

 long labyrinthic coils. 



Of peculiar interest are the minute detached jaws and denticulated plates 



Pig. 220. 



Eunicites avitus Ehlers. 

 Stone ; Eichstadt, Bavaria 



Lithographic 

 Natural size. 



