82 
PATAGONIAN EXPEDITIONS : PALEONTOLOGY. 
interlock, as in Protypotherium (Pis. II, fig. 1 8 ; V, fig. 2). Distally, 
strongly developed keels are present on the plantar surfaces. 
No associated series of phalanges are preserved. Such representatives 
of the first and second rows as are known are scarcely distinguishable, 
except in point of size, from those of Protypotherium , except that the 
phalanges of digit V in Hegetotherium are extremely slender. The ter- 
minal phalanges (PI. II, fig. 21) maybe readily recognized by their broad, 
hoof-like character and terminal clefts. 
Hegetotherium mirabile Ameghino. 
(Plates I, II; Text Figs. I , D \ 4, A ; 13-16.) 
Hegetotherium mirabile Amegh.; Enum. Sistematica, etc., p. 14, 1887. 
Hegetotherium strigatum Amegh.; ibid., p. 14, 1887. Lydekker, Anales 
del Museo de La Plata, Palaeontologia Argentina II, article 3, p. 8, 
PI. I, figs. 3, 4, 1893. 
Hegetotherium cuneatum Amegh.; Revista Argentina de Hist. Nat., I, p. 
291, 1891. 
Hegetotherium costatum Amegh.; ibid., p. 291, 1891. 
Selatherium pachymorphum Amegh.; Enum. Synoptique, etc., p. 20, 1894. 
Selatherium remissum Amegh.; ibid., p. 20, 1894. 
The preceding account of the osteology of Hegetotherium is based 
entirely on remains of this species, which is represented in the collections 
at Princeton University and the American Museum of Natural History 
by a large suite of specimens from localities as follows : Killik Aike (5), 
two miles west of Killik Aike (1), Canon de Palo (1), ten miles south of 
Coy Inlet (7), five miles south of Coy Inlet (3), Coy Inlet (1), seventeen 
miles north of Cape Fairweather (1), ten miles north of Cape Fairweather 
(1), Cape Fairweather (2), Felton’s estancia, Rio Gallegos (2), Halliday’s 
estancia, Rio Gallegos (1), seven miles south of Monte Leone (1), fifteen 
miles south of Monte Leone (1), forty miles south of Santa Cruz (1), ten 
miles north of Coy Inlet (1). 
In each case the figures in parentheses refer to the number of individuals * 
from the locality mentioned. 
As but one species is represented, the generic and specific characters 
cannot be separated. Nos. 15,542, 15,432, 15,505, 15,093, 15,298, 15,43b 
15,176, 15,392, and Nos. 9223 and 9156, American Museum, are figured 
on Plates I and II. 
