NO. 2177. FOSSIL FISHES IN NATIONAL MUSEUM— EASTMAN. 



247 



natiu-e, it is not capable of precise systematic determination. The 

 text-figure 2, copied from a recent paper by Dr. W. K. Gregory, per- 

 mits of a comparison of the cranial pattern of Diyterus and Scaumen- 

 acia. In still later studies by D. M. S. Watson and Henry Day (1916), 

 slightly different homologies are recognized than tliose here indicated. 



Fig. 2.— Pattern of skull-top of Devonian Dipnoans. A, dipteeus valenciennesi, after Good- 

 rich, SLIGHTLY MODIFIED BY W. K. GREGORY. B, SCAUMENACIA CURTA, AFTER HUSSAKOF. In 



SPEaMENs OF Dipteeus the numerous sensory pits are scattered over broad tracts, the gen- 

 eral DIRECTIONS OF WHICH ARE INDICATED BY THE DOTTED LINES, EXCEPT IN THE OCaPIT.U. REGION WHEEE 

 THE DOTTED LINES EEPEESENT SHALLOW GROOVES. THE "PAEIETALS," "FRONTALS," ETC., ARE PROB- 

 ABLY NOT HOMOGENOUS WITH THOSE OP TeTR.VPODA. DsO, DERMOSUPRAOCCIPITAL; Fr, FEONTALS; Na, 



NASOETHMOiD region; S^supratempoeal (pterotic); rfijTABULARECEPioTic); Parietal, PREPARIETAL. 



DIPTERUS ANGUSTUS (Newberry). 



Plate 8, fig. 5. 



Sagenodiis angustus Newberry, Trans. N. Y. Acad. Sci., vol. 16, 1897, p.; 303, 

 pi. 24, fig. 26. 



The holotype, and until recently, the soUtary known example of 

 this species, is a worn and imperfectly preserved dental plate from the 

 Catskill of Bradford County, Pennsylvania, now the property of the 

 American Museum of Natural History. The illustration given of it in 

 Newberry's posthumous paper is imsatisfactory, as it would seem to 

 represent a complete tooth, disengaged from the matrix, and with 

 nearly smooth superficial ridges. In pouit of fact the tooth is em- 

 bedded in a block of hard sandstone, and the extermal margin is par- 

 tially concealed by matrix, so that the entire outline of the tooth is 

 not visible. Moreover, although the oral surface is considerably 

 worn, it is plain that aU of the ridges were tuberculated, this condi- 

 tion being very distinct in the two posterior ridges. As noted by 

 Newberry, the anterior ridge is widely divergent from the others 



