PALEOZOIC TIME — DEVONIAN. 



619 



pertain, were described from specimens found in the Cleveland shale of Ohio. 

 Fig. 965 shows the form of the upper and lower jaws in natural position of 

 Dinichtkys Hertzeri. To represent the natural size, the figure should have a 

 breadth of 45 inches. Fig. 966 is the ventral shield. It resembles that of 

 Coccosteus, and also that of Bothriolepis. A still larger species is the 

 Titcmichthys Clarki of Kewberry, in which the head was four feet or more 

 broad, the lower jaw a yard long. This jaw was shaped posteriorly like an 

 oar blade, and anteriorly was turned upward like a sled-runner. Dinichtkys 

 Gouldi of Newberry had enormous eyes surrounded by sclerotic plates. The 

 Phaneropleuron of Whiteaves (Fig. 969) is a smaller Dipnoan from the 

 Upper Devonian at Scaumenac Bay, j^ew Brunswick. Figs. 967, 968 rep- 

 resent the palate teeth of two Dipnoans ; such teeth, and the brachiate pec- 

 toral and ventral fins are special Dipnoan characteristics. 



975-977. 



Selachians. —975, Cladodus sinuatus (x J) ; 976, tooth of C. Clarki ; 977, C. Fyleri (x|). Figs. 975, 976, Claypole ; 



977, Newberry. 



Fig. 970 represents a Ganoid of Crossopterygian type — as indicated in 

 this figure by the thickened finger-like medial portion of the pectoral fin — a 

 structure better exemplified in Fig. 969. A scale of a related genus, 

 Holoptychius, is represented, of natural size, in Fig. 972, and a tooth, referred 

 to the same genus by Leidy, in Fig. 973. (See also page 625 for a figure of a 

 nearly complete specimen of another species.) The genus Eustheyiopteron of 

 Whiteaves (Fig. 971) has special interest on account (as the name implies) 

 of the supports with which the fins are provided, answering to the pectoral 

 and pelvic arches of higher Vertebrates — a, the pectoral, and h, the pelvic 

 (only two bones of which are preserved) ; and also the similar and even 

 larger supports for the anal fin at c and for the posterior dorsal at d, with a 



