Sub-Kingdom IV. VERMES. Worms. 1 



I!/l<it< rail// symmetrical animals with unsegmented or uniformly segmented, and 

 elongated, bodies. Segmented lateral appendages wanting. A dermal 

 muscular system and paired excretory canals (water-vascular system) present. 



Of all the larger divisions of the animal kingdom, none is so poorly 

 adapted for preservation in the fossil state as the Worms, whose bodies, as a 

 rule, are totally without hard parts. 



All Worms are laterally symmetrical, and in every case a dorsal and 

 ventral surface is distinguishable. The group of unsegmented Worms (Vermes 

 proper, as restricted by some authors) have either flat or cylindrical bodies, 

 and are accordingly distinguished as Plaf-yhelminthes or Flat Worms, and Nema- 

 thelminthes or Round Worms. But with the exception of a few rare parasitic 

 forms discovered in Carboniferous insects, or in insects enclosed in amber, 

 neither of these classes is represented in the fossil state. 



The segmented Worms, or Annelida, are characterised by a division of the 

 body into metameres, which, although primitively alike, do not always remain 

 homonomous. They have a brain, a circumoesophageal ring, a ventral chain of 

 ganglia, and a vascular system. The body is more or less elongated, and 

 sometimes flattened, sometimes cylindrical. According as the internal 

 segments correspond exactly with the external, or as each internal segment 

 corresponds to a definite number (3, 4, or 5) of the external rings, two 



1 Literature : 

 Pander, C. H., Monographic der fossileu Fisclie <k's silnrischen Systems cles russisch-baltischen 



Gouveruemeuts, 1851. 



Ehlers, E., Die Borstenwiirrner (Annelida Chaetopoda). Leipzic, 1864-68. 

 Ehlers, E., Ueber fossik- Warmer aus dem lithographischeu Schiefer in Bayeru (Palaeontographica, 



Bd. XVII.), 1868. 



Claparede, E., Recherches sur la structure des Annelides scklentaires, 1873. 

 Neivberry, J. S., Palaeontology of Ohio, vol. II. part 2, 1875. 

 Hinde, G'. J., On Conodonts from the Chazy and Cincinnati Groups ; and on Annelid Jaws from the 



Cambro-SiluriftD, Silurian, and Devonian Formations in Canada, and from the Lower Carbon- 

 iferous in Scotland (Quar. Journ. Geol. Soc., vol. XXXV.), 1879. 

 Hinde, G. J., On Annelid Jaws from the Weulock and Ludlow Formations of the West of England 



(Quar. Journ. Geol. Soc., vol. XXXVI.), 1880. 



Etheridge, R., jun., British Carboniferous Tubicolar Annelides (Geol. Mag.), 1880. 

 Nathorst, A. G., On the Tracks of some Invertebrate Animals and their Palaeontological Significance 



(K. Svensk. Vetensk. Akad. Handl., Bd. XVIII., XXL), 1881-86. 

 Hinde, G. J., On Annelid Remains from the Silurian Strata of the Isle of Gotland (Bihang till K. 



Svensk. Vetensk. Akad. Handl., Bd. VII.), 1882. 

 Zittel, K. A., and Rohon. J. V., Ueber Conodonten (Sitzungsber. Bay. Akad. Wissensch., Bd. XVI.), 



1886. 

 Clarke, J. J/., Annelid Teeth from the Lower Portion of the Hamilton Group, New York (Sixth 



Annual Report State Geologist, 1886). 



