784 THE AMERICAN NATURALIST. [Vou. XXXIII. 
occupied, having been applied to a Hybodus by Reuss in 1846.1 
The first-mentioned species may be renamed H. copei. 
In 18662 Newberry and Worthen described, from the Bur- 
 lington limestone of Iowa, a tooth which they called Helodus 
compressus. This species is now regarded as belonging to the 
genus Hybocladodus. In 1870 the same writers described 
another Helodus compressus, from the same horizon, in Illinois. 
In renaming the latter species I shall, by calling the fossil Æ. 
qworthent, endeavor to honor the director of one of the most 
creditably conducted of our state geological surveys. 
The name Stemmatodus was applied in 18754 by St. John 
and Worthen to certain bodies-which they regarded as teeth of 
shark-like animals, but which may be, as Mr. A. S. Woodward 
has suggested, dermal denticles. The name had, however, 
been employed by Heckel in 1856 for a genus of pycnodont 
fishes. Clearly the name, as employed by St. John and Worthen, 
must yield to some other term. I propose StEmMMatTias. The 
type will be Stemmatias cheiriformis St. John and Worthen. 
The recognized species are S. bicristatus, S. bifurcatus, S. com- 
pactus, S. keokuk, and S. symmetricus, all described by the 
authors referred to. ; 
The name Goniodus was employed by Agassiz® in 1838 to 
designate a genus of sharks which had previously been called 
by Blainville Echinorhinus. Being therefore a synonym of 
Echinorhinus, it is not available as the name of any other 
genus. Nevertheless, it was in 1889 applied by Newberry ê to 
certain pavement-like teeth from the Huron shales of Ohio. 
As a substitute for Dr. Newberry’s name, Mr. S. A. Miller, 
in 1893,’ proposed the name Xenodus. The type and only 
known species is X. hertzeri (Newberry). 
In 18628 Morris and Roberts applied one of Agassiz’s manu- 
1 Verstein, bihm. Kreidef., pt. ii, p. 98. 
2 Geol. Surv. dll, vol. ii, p. 78, Pl. V, Fig. 1. 
8 Geol. Surv. Til., vol. iv, p. 360, Pl. III, Fig. 15. 
4 Geol. Surv. Til., vol. vi, p. 328. 
5 Poissons Foss., vol. iii, p. 94. 
8 Palaoz. Fishes N. A., p. 67. 
T N.A. Geol. Paleont., ist App., p. 718. 
8 Quar, Journ. Geol. Soc., vol. xviii, p. 101. 
