258 ZAGLOSSUS. 
(1905) states that in his series of nine Proechidnas are specimens even more ~ 
thickly haired than Dubois claimed for the type of villosissima, but adds that ~ 
he and Dr. Hartert differed as to which should be considered young animals, 
for there was no way of comparing the skulls. The dense character of the pelage 
may be retained in the adult, as is the case apparently of the specimen from 
British New Guinea, made the type of the race bartont by Thomas. The 
thickness of the hairy coat can not of itself be considered a specific character 
since even the small series of specimens at hand shows much variation in this 
respect. Possibly the extreme condition shown by the villosissima specimens 
is in part a concomitant of youth, as has been suggested by earlier writers. 
The lack of definitive cranial characters, together with the absence of trenchant 
differences in external features or geographical range, seems sufficient ground 
for relegating villosissima to synonymy under bruijnit. 
To recognize four or five races of Proechidna all of which may occur to- 
gether in the western peninsula of Papua seems a rather anomalous proceeding, 
particularly since these are not separated by any structural peculiarities. The 
case is somewhat paralleled by that of the Australian Echidna in which the range 
of variation is so great as to have led at various times to the recognition of 
several races, although now but one form is accorded to that continent. While 
I have not seen the type of either bartoni or goodfellowi, a careful study of 
the descriptions of these two races does not reveal any diagnostic charac- 
ters, and it seems best to consider these names for the present, at least, as 
synonyms. 
As long ago as 1868, Krefft reported the discovery of Echidna-like remains 
in the Wellington bone and breccia caves of New South Wales, Australia, and 
he figured a portion of a humerus. Later, Owen made further reports on addi- 
tional fragments discovered in these caves. He figured a nearly complete 
humerus that appears to belong to Zaglossus rather than to Tachyglossus as 
I shall later show. This important discovery points to the former coexistence 
of the two genera in Australia, and is of special interest in its zodgeographic 
bearing, since at the present day both are foundin New Guinea; but the Echidna 
alone survives in Australia. It follows therefore that the Proechidna was 
already well differentiated from the Echidna long before Papua was sundered 
from Australia, so that it is not a recent Papuan derivative from an Echidna 
stock, developed here through isolation. But rather the two genera have long 
existed side by side. 
The distinctive characters of the Australian fossil Proechidna are insuffi- 
