@ 
SYNETHERES. 169 
specimens of 0. degus when he returned to Europe, Dr. v. Frantzius unhesitatingly 
referred his lost specimen to that species*. It appears to me, however, that the above 
description might apply as well to a Hesperomys of the subgenus Nyctomyst as to an 
Octodon. 
As far as I am aware, no species of Octodon has yet been met with further north than 
the Peruvian Andes, while the Coypu does not appear to advance beyond Central Chilif. 
Both forms are highly characteristic of the Patagonian subregion; and their occurrence 
in Central America is extremely improbable. 
Fam. V. HYSTRICIDZ. 
1. SYNETHERES. 
Coendu, Lacépéde, Mém. de V’Inst. Nat. iii. p. 496 (1801) §. 
Synetheres et Sphiggurus, Fréd. Cuvier, Mém. du Mus. ix. p. 427 (1822) |f. 
Cercolabes, Brandt, Mém. Ac. Pétersb. (6™° sér.) iii. p. 391 (1835). 
Of the three American genera of Porcupines constituting the subfamily Synetherine, 
the typical genus Synetheres is clad with short spines more or less mixed with long 
harsh hair, and has a long prehensile tail. The hind feet have only four toes, but their 
soles are expanded on the inner edge by a broad lobe which is supported by two accessory 
tarsal ossicles. 
All the species are Neotropical, their place being taken in North America by the 
allied genus Hrethrizon. The only one found in Central America, Synetheres mexicanus, ° 
belongs to the section or subgenus Sphingurus, in which the spines are hidden by the 
long hair. It is at once distinguished from its nearest allies, S. vi//osus, F. Cuvier, and 
S. melanurus, Wagner, by its black colour and by the tufts of spiny bristles which are 
concealed by the fur of its lower parts. The length of the head and body is about 
20" to 22”, and of the tail 12” to 16”. 
* Tom. cit. pp. 275, 276. 
+ Cf. supra, p. 143. 
£ Dr. v. Tschudi included Myopotamus coypus as a Peruvian animal in his ‘Mammalium Conspectus’ (Arch. 
f. Naturg. x. 1, p. 252), but afterwards withdrew it as unauthenticated (‘Fauna Peruana,’ p. 184). 
§ Cf. supra, p. 3, footnote. 
|| The laws of nomenclature requiring that one of Cuvier’s names should be retained for this genus, which 
Brandt had shown to be indivisible, I formerly preferred to use his second title, in an amended form, and 
called the subfamily Sphingurine (P.Z.8. 1876, p. 93). But Mr. J. A. Allen has since pointed out (Mon. 
N.-Am. Rodent. p. 385) that Gervais had already founded the group on Synetheres (Zool. et Paléont. Franc. 
p. 18); and it is evident that his example should be followed to prevent confusion. 
BIOL. CENT.-AMER., Mamm. Vol. 1, October 1880. Z 
