1 66 NEW YORK STATE MUSEUM 



tinuous plate with the adjoining elements ; no parietal or frontal foramen ; 

 interoperculum absent ; jugular plates comprising one large pair, flanked on 

 either side by a lateral series. Dentary bone of mandible thin and deep, 

 bearing a series of small teeth, and with well developed infradentaries, much 

 bent inwards below ; an inner series of few, large, broad, shuttle-shaped 

 bones, each supporting a "laniary" tooth; a pair of similar teeth on the 

 roof of the mouth, but the marginal upper dentition feeble. Teeth conical, 

 with a very small pulp cavit)', of which the walls exhibit complex infoldings, 

 appearing closely intertwined when viewed in transverse section, these pro- 

 ducing superficial vertical flutings. Pectoral fins acutely lobate, pelvic fins 

 either acutely or obtusely lobate ; two remote dorsal fins ; anal fin single ; 

 caudal fin diphycercal or heterocercal. 



The foregoing family definition, which we have taken from Smith 

 Woodward, is based chiefly upon the structural characteristics of the typical 

 genus Holoptychius, well preserved specimens of which occur plentifully in 

 the Scottish Old Red sandstone, and are known also from Belgium and 

 Russia. With the exception of the closely related Glyptolepis q u e- 

 becensis Whiteaves,' by some writers included with Holoptychius, no 

 member of this family is represented in the American Devonic by com- 

 pletely preserved remains, and by far the majority of species are founded 

 upon detached scales. The teeth described by Leidy under the name of 

 Apedodus prise us," from the Catskill of northern Pennsylvania, 

 examples of which are figured in plate i, figures i, 2, do not appear to differ 

 from those of Holoptychius by any recognizable characters. On the other 

 hand the accompanying S a u r i p t e r u s t a y 1 o r i,^ founded on portions of a 

 fish closely similar to Holoptychius, is proved by the less complicated struc- 

 ture of the teeth and obtusely lobate condition of the pectoral fins, to agree 



' Whiteaves, J. F. Roy. Soc. Can. Trans, v. 6. (1889). § 4, p. 77, pi. 5, fig. 4. 



^ Leidy, J. Acad. Nat. Sci. Phila. Jour. ser. 2. v. 3. 1856. p. 164, pi. 17, fig. 5, 6. 



3 Hall, J. Nat. Hist. New York, pt 4. Geology. 1843. p. 282, text fig. 130. The 

 same specimen is further noticed by J. S. Newberry, U. S. Geol. Sur. Monogr. 1889. 

 16: 112, but is not figured. Type preserved in the American Museum of Natural History, 

 New York, 



