30 E. B. BRANSON 



Sandalodus alatus Newberry and Worthen 



(Plate I, Figs. 3-5) 

 Deltodus alatus Newberry and Worthen, 1870 {Paleontology of Illinois, Vol. IV, 



Plate II, Fig. 6, p. 368). 

 Deltodus alatus Woodward, 1889 {Catalogue 0} Fossil Fishes in British Museum, 



Part I, p. 199). 

 Deltodus spatulatus Eastman, 1903 {Bulletin of the Museum of Comparative 



Zoology at Harvard College, Vol. XXXIX, p. 198). 



In a paper published in 1903 (loc. cit., p. 198) Eastman gives 

 Deltodus alatus as a synonym of D. spatulatus. The specimens of 

 D. alatus teeth in the collection of Walker Museum are all more or 

 less fragmentary, but they present the following characters which 

 serve to distinguish them from D. spatulatus. The pores in the 

 enamel are much larger and fewer in number. The average number 

 per square millimeter being four in D. alatus and seven in S. spatula- 

 tus. The postero-lateral border of D. alatus teeth has a broad, thin 

 alation extending its full length. Near the outer end this alation is 

 much broader than the accompanying ridge. In the posterior teeth of 

 D. spatulatus the alation is not broad, but it is thick, and it disappears 

 near the outer end. D. alatus teeth have a thin, narrow alation 

 along the antero-lateral border, while the antero-lateral border of 

 D. spatulatus teeth is thick, has no alation, and is modified for the 

 attachment of other teeth. 



This species is referred to Sandalodus because it seems to have 



but a single tooth to each ramus of the jaw. 



Formation and locality: Keokuk and Burlington limestones; Iowa and 

 Illinois. 



Sandalodus porcatus sp. nov. 



(Plate I, Fig. 14) 

 Type a single incomplete tooth. Length along antero-lateral edge, 34 mm ; 

 breadth above alation, 14™™; greatest thickness, io mm . As the outer part of 

 the "halation is missing, its full dimensions cannot be ascertained. Tooth very 

 thick and strong at the inner end, but becoming thin along the antero-lateral 

 border near the outer end. The postero-lateral border is thick from the outer 

 end to the alation, but becomes quite thin along the margin of the alation. The 

 alation resembles that of 5 1 . emarginatus in being convex upward and very thick 

 and strong. It occupies considerably more than half the postero-lateral border 

 of the tooth, and diverges from this border at an angle a little greater than ioo°. 

 Tooth strongly arched longitudinally and transversely, excepting at the outer 

 end, where the transverse arching is much less than in S. laevissimus and S. 



