FOSSIL FISHES. 41 



FISHES OF THE CARBONIFEROUS SYSTEM. 



MARSIPOBRANCHIK?) 



" GONOnONTSy 



Plate LVII. 



In the first volume of this Report reference was made in several places 

 to certain minute, coinb-Iike oi' tooth-like organs, found in great numbers 

 in the Cleveland shale of the Waverly group at Bedford, Cuyahoga 

 county. They are from one-twentieth to one-fourtli of an inch in lengtli, 

 and usually consist of a narrow, compressed, slightly arched base, from 

 which spring numerous flattened denticles. These are generally long 

 lance-shaped, and very acute at the margins and summits (see Figs. 1, M, 

 12, 14, 16, 18, 19, 20). 



Occasionally they are in part rounded and obtuse (Figs. 3, 9, 10, 15), 

 but much oftener are acute and somewhat subulate. A not uncommon 

 form is represented by Figs. 4 and 8. In this variety the base is elon- 

 gated and narrow, in a few cases rod-like, and but slightly curved. From 

 this base rises a series of denticles of nearly uniform size, connected by 

 (oaie.cing intermediate ones of two-thirds their height; the wliole form- 

 ing a tin-like margin or wing. Still another variety is seen in Fig. 1. 

 In this the teeth are fine and closely approximated, and the organ has a 

 wonderful likeness to an elongated comb. 



The material of which the Conodouts are composed is slightly translu- 

 cent, horn-like in color, and closely resembles the enamel of many teeth. 



The number of these objects is immense, and the variety of form 

 which they exhibit, is but imperfectly shown in tlie figures now given. 

 In regard to their zoological relations it is as yet quite impossible to 

 speak with certainty. The Conodonts found by Prof. Pander in the 

 Lower Silurian marls of St. Petersburg, Russia, were considered by him 

 to be the teeth of small sharks. This conclusion has not been generally 

 accepted by other palaeontologists, though no perfectly satisfactory expla- 

 nation of their zoological relations has been offered. Prof. Owen (Palae- 

 ontology, p. 116), discusses their structure and affinities at considerable 

 length, and concludes that " they have most analogy with the spines, 

 booklets, or denticles of naked mollusks, or annelids." 



