88 Cincinnati Society of Natural History. 



ination he concluded that they were the hard chitonous parts (hooks) 

 of annelids. He coins for them the generic name, JSfereidavus, from Ne^ 

 reis, an existing genus, and to which he considers them probably re- 

 lated. 



Through the kindness of Prof. Wetherby, I have been enabled to ex- 

 amine several species of the genus JVeries, and among them the Nereis 

 jjelagica, Lin,, a species esi>ecially mentioned by Mr. Grinnell, and found 

 a striking resemblance between their jaws or hooks, and the little Con- 

 odonts that are so common in our rocks. 



On account of the great diversity of opinion with regard to the zoolo- 

 gical affinities of these remains, which have been expressed by un- 

 doubted authorities, it would be rash for rae to assert that they are the 

 chitonous jaws of annelids. They present so little from which accur- 

 ate conclusions can be drawn, and for that reason all the theories that 

 have been advanced to solve the enigma are based on some points, of 

 which they give a possible, and in some cases an altogether probable 

 explanation. Without, then, going farther into the merits of the above 

 theories, we will, for the present, accept the one which seems to aftbrd 

 the most probable explanation, and assume that the Conodonts and 

 Nereidavus are the booklets of species of annelids. 



In that case, we can easily imagine that the ocean beneath which 

 the Cincinnati group was deposited, at times swarmed with innumer- 

 able worms, which have, so far as we at present know, left no traces of 

 themselves excepting their jaws, tracks, and possibl}^ a few rude im- 

 pressions of their bodies. 



Whei'e the number is so great of one group of these annelids, we 

 can scarcely suppose that it was the only one existing, but it stands 

 more to reason to suppose that other groups flourished, which had no 

 parts capable of being fossilized, and therefore left no traces excepting, 

 perhaps, their burrows ; and still others again, possibly large groups, 

 which the i)ahieontological collector has as 3'et not unearthed, but some 

 of which he will undoubtedly bring to light in the future. The iirst 

 evidences that we have of vermes, are from the Huronian group. These 

 were named ArenlcoUtes, hj Salter, and are simpl}'' circular holes, ap- 

 pearing in twos on the surface of sandstones, and bearing much resem- 

 blance to the burrows of the worm Arenicola. The next we find in 

 JSTereidavus and the Conodonts, which have been found in nearly all the 

 formations from the Trenton to the Coal Measures. 



In the Cincinnati group, we find that besides the Nereidavus, Miller 

 and Dyer have described, in the first number of the Journal of the 

 Cincinnati Society of Natural History, another form, for which the}' 

 erected the Genus Walcotia, and named W. riir/osa. The fossils to 

 which they attached this name are casts, which are not very rare in 

 the quarries about Cincinnati, having short lint-ar depressions diverg- 



