SCOTT: ENTELONYCHIA OF THE SANTA CRUZ BEDS. 247 
Homalodontotherium Flower ; Phil. Trans. Roy. Soc. London, Vol. 
CLXIV, 1884, p. 173. 
Homalodon Burmeister; Anales del Mus. Nac. de Buenos Aires, T. Ill, 
1891, p. 389. 
Homalotherium Ameghino ; Ibid., T. XV, 1906, p. 317 [err ore). 
It is customary to attribute this genus to Huxley, but it is much more 
properly referable to Flower. The name proposed by Huxley is the 
baldest nomen nudum , as becomes perfectly clear when the original ac- 
count (it cannot be called a description) is read. “Still more perplexing 
are the strange and interesting forms Toxodon, Macrauchenia , and Typo- 
therium , and a new Anoplotherioid mammal ( Homalodotherium ) which 
Dr. Cunningham sent over to me some time ago from Patagonia.” (Hux- 
ley, loc. cit.) The first description of the genus was given by Flower 
(/oc. cit.) who adopted Huxley’s name in emended form. I am unable to 
comprehend the course followed by Dr. Palmer in his admirable “ Index 
Generum Mammalium”; he attributes the genus to Flower and yet re- 
tains Huxley’s name, which is marked “nomen nudum.” This is a self- 
contradictory procedure, since a nomen nudum can have no rights of 
priority (Palmer, ’04, 330). 
Homalodontotherium is a comparatively rare member of the Santa Cruz 
fauna and the Princeton and New York collections contain but little 
material illustrating it. In the La Plata Museum are the valuable speci- 
mens which have been figured and briefly described by Lydekker (’93^ 
44-47) and the genus is very well represented in the collection of Dr. 
Ameghino. It is from this material, as well as from the publications of 
Flower, Ameghino, Lydekker and Gaudry, that the following account has 
been chiefly drawn, through some of the specimens collected by Messrs. 
Hatcher and Peterson have proved very useful. Thanks principally to 
the work of Ameghino, the structure of these very curious animals is now 
fairly well known and their systematic position may be made reasonably 
clear. 
Dentition. — The dental formula is unreduced ; If, Cf, PI, Mf ; as Flower 
has pointed out, the teeth, which in both jaws are arranged in unbroken 
series, “ in their configuration present a remarkable and gradual transition 
from the first incisor to the last molar, easily traced in both jaws, and 
more even and regular than in any other known heterodont mammal” 
(’84, 175). At the time when this description was written, the dentition 
