G08 MONOGRAPHS <>K NORTH AMERICAS RODENTIA. 



named Ascomys inexicanus l>y Lichtenstein, and his accounl may be the earli- 

 esl literature of the subject. We have no Linnsean name in this family. 

 Bart ram noted the Floridan animal in 1791 ; bul the first "species" pre- 

 sented in technical nomenclature appears to be the Mus bursarius of Shaw 

 (1800). The earliest generic names are Geomys and Diplostotna, imposed by 

 Rafinesque in 1817. Various circumstances conspired not only to a vague 

 understanding of (he generic characters, bul also to long delay in allocation of 

 the genera under major heads. Richardson, who, in 1829, handled various 

 species more effectively than his predecessors hail 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" Arvicolidce. 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 

 Saccomyimi to contain them both. Gervais is said to have established or 

 recognized at the same time a family Pscuilostoiuidee, 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 Saceomyine forms elsewhere. Geomyince. of- Baird, Alston, and 

 others, and Geomyida of Gill anil Coues, are other terms of exclusive 

 pertinence to this group, which certainly belongs to the Myomorphic 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 affinities with Saccomy/dce, perhaps remains open. Its 

 Murine affinities may perhaps prove to have been indicated by the name 

 Brandt applied, but its Sciurine relationships arc not so clear. 



* 1855 — BRANDT (.1. 1'.). Beitriige zur niihern KeDntniss der Siiugethiere Eusslauds. Vierte 

 AMiandlung. Blicke auf die allmiiligeu Fortschritte in der Grnppirnng dor Nager, mit Bpecieller Bezie- 

 hnng auf die Geschicbte der Gattuiig Castor, besonders der altweltHcben Biber. 4to. St. Petersburg. 

 1855. pp. 59-336, pi. i-xi (Aus den Mem. Math, etc., do l'Acad. Imp. dea Si iences, tunic v i, besoudera 

 abgedriu-kt.) 



[Sciurospalacoides, p. 300. Related groups established in tliis paper an- Maerocoliui (=Dipotloui>y), p. 2.11 ami p. 

 311, ami Per>><i:tatli : li ■ liuroapalncoides, p. 305.] 



