608 MONOGRAPHS OF NORTH AMERICAN RODENTIA. 
named Ascomys mexicanus by Lichtenstein, and his account may be the earli- 
est. literature of the subject. We have no Linnean name in this family. 
Bartram noted the Floridan animal in 1791; but the first “‘species” pre- 
sented in technical nomenclature appears to be the Mus bursarius of Shaw 
(1800). The earliest generic names are Geomys and Diplostoma, imposed by 
Rafinesque in 1817. Various circumstances conspired not only to a vague 
understanding of the generic characters, but also to long delay in allocation of 
the genera under major heads. Richardson, who, in 1829, handled various 
species more effectively than his predecessors had done, merely adopted 
Rafinesque’s genera, falling into a misunderstanding respecting the character 
of the pouches. So far as I am aware, after the period when ‘‘Mus” and 
““Cricetus” 
were current appellations of these animals, the first attempt to 
dispose of them in a formal classification was made by Waterhouse in 1839, 
when he treated of Geomys, the only genus recognized by him, as a Muroid, and 
as a member of his “family” Arvicokde. The same year (1839), Maximilian 
established the second valid genus, Thomomys, the various generic names 
before proposed having been synonyms of Geomys. In 1848, Waterhouse 
made the first decided step toward a correct appreciation of the subject, by 
bringing Geomys into. relation with Dipodomys, and by proposing the group 
Saccomyina to contain them both. Gervais is said to have established or 
recognized at the same time a family Pseudostomide, equivalent to Water- 
house’s Saccomyina. Soon afterward, in 1855, Brandt* established the first 
super-generic name Sciurospalacoides for these animals exclusively, relegat- 
ing the Saccomyine forms elsewhere. Geomyine of Baird, Alston, and 
others, and Geomyide of Gill and Coues, are other terms of exclusive 
pertinence to this group, which certainly belongs to the Myomorphie series of 
Rodents, as originally sketched by Waterhouse and more fully developed by 
Alston, though the question of its exact position among Myomorpha, aside 
from its obvious afhnities with Saccomyide, perhaps remains open. Its 
Murine affinities may perhaps prove to have been indicated by the name 
Brandt applied, but its Sciurine relationships are not so clear. 
*1855—Branpr (J. F.). Beitriige zur niihern Kenntniss der Siugethiere Russlands. Vierte 
Abhan@lung. Blicke auf die allmiiligen Fortschritte in der Gruppirung der Nager, mit specieller Bezie- 
hung auf die Geschichte der Gattung Castor, besonders der altweltlichen Biber. 4to. St. Petersburg. 
1855. pp. 79-836, pl. i-xi. (Aus den Mém. Math. ete.,de ’Acad. Imp. des Sciences, tome v.i, besonders 
abgedruckt.) . 
[Sciurospalacoides, p. 300. Related groups established in this paper are Macrocolini (—Dipodomys), p. 231 and p. 
311, and Perognathi seu Mures sciurospalacoides, p. 305.) 
