|SS MONOGRAPHS OF MOBTE1 AMERICAN BODENTIA. 



A group Saccomyina,* under a family Muridee, was established in 1848 by 

 G. R. Waterhouse to contain all 1 liose American Rodents which have external 

 cheek-pouches, and consequently included the genera Geomys and Tkomo?ny.i, 

 as well as those jusl specified. Such comprehensive acceptation of the group 

 as a family was endorsed by Baird in 1857, f and more recently by Mr. K. R. 

 Alston. J These authors agree, furthermore, in dividing the Saccomyida, as 

 understood by Waterlionsr, into two subfamilies; Professor Baird's groups 

 being Saccomyina} -\- Geomyinee=zSaccomyid&, while Mr. Alston, with unnec- 

 essary § change of nomenclature, makes Geomyince-\-Ifeteromyin(e—Geom.y- 

 id(E. Thus a nominal disagreement is brought about, when really these two 

 authors arc at one, both in their valuation and their definition of the groups in 

 question. || 



I accept the groups as originally indicated by Waterhouse, and as limited 

 by Baird and Alston, but I differ in my valuation of them, considering that 



•■ Saccomyina" — a name informally proposed iu the text, p. 8, vol. ii, of the Nat. Hist. Mainni. 

 (1848), as the " provisional" designation of a group of no assigned valuation, wi Lb the following definition 

 in a foot-note: — 



"A group of Rodents found in North, and Central America, and in some of the West India Islands ; 

 all the species of which possess cheek-poaches, opening externally ; I hey have — molar teeth. Iu some 

 the teeth arc root less, and the tail is short ; they constitute the genus ("i corny s ; iu others the tail is long, 

 and the molars are rooted, as in the genus Heteromys, Saccouiys, and Peroguathus. Dipodomys no doubt 

 also belongs to this section, which I provisionally form for genera which there appear to bo good reasons 

 thus to unite." (See also K. Johnston's ed. of Berhaus's Physical Atlas, Tabic of theOrdets Kodentia and 

 Rnminantia, No. 5, folio, Edinburgh, 1849.) 



In his earlier papers, Waterhouse had placed Geomys among true Murine forms in a "family" 

 Arvivolidw. See " Observations on the Rodentia, with a view to point out the groups, as indicated by tho 

 structure of the Crania, in this order of Mammals." < Charlesw. Mag. N. II. viii, 1839, pp. 90-96, 184- 

 188, 274-279, 593-C00 ; wood-cuts. (See also Ann. Mag. Nat. Hist, viii, 1841, pp. 81-84 ; x, 1842, pp. 197- 

 203, 344-347 ; and P. Z. S. 1839, pp. 172-174.) 



t Mammals of North America, p. 305 (4to, Washington, lS. r >7). 



t On the Classification of the Order Glires. . < Proc. Zoiil. Soc. Loud., Jan. 1870, pp. 01-98, pi. iv. 

 (See especially pp. 19 and 87.) A paper no student of the Rodentia should fail to consult. 



$ I cannot agree with Mr. Alston that, because Fred. Cuvier's genus Saccomys is doubtless a synonym 

 of Heteromys Desm., iD is iu. consequence uecessary to derive the name of the subfamily from the latter, 

 and speak of Heteromyiiuc instead of Saceomyinw. It is always admissible to derive the name of a sub- 

 family or family from any one of its component genera, though, of cotirse, desirable that such namo 

 should indicate a characteristic or otherwise leading generic type. Hence, though Saccomys is an 

 undoubted synonym, it is not necessary to discard the terms Saceomyinw and Saccomyida, long established 

 and iu general employ, as well as suggestive and pertinent. 



|| Brandt, perhaps alone among late leading writers, dissents from the views here implied. " Iu his 

 recent paper on the classification "of the Rodentia iu Beitriige znr nahern Kenntuiss dcr Siiujrethiero 

 Russlands, 1-.",:,, i»s i [he] establishes a family of Sciuro-spalacoides to contain Geomys and Thomomys, as 

 constituting a connecting link between the Sciuriaw and a family of Spalacoides, typified by Spalax, 

 Siphneus, Ellobius, Ac. He dissents from the views of Waterhouse in combining Geomys and Thomomys 

 into a family with Perognathus and Dipodomys. Perognathus he considers rather as a Muroid, and coming 

 next to Cricetus, while Dipodomys, or rather Macrocolus, is placed as the type of a sub-family Maerocolini 

 under the Dipodoidcs. I think, however, a revision of the subject, with more ample materials before him, 

 will satisfy this eminent zoologist of the soundness of Waterhouse's view." — (Quoted from Baird, M. N. 

 A., pp. 31)5-0, as pertinent to the history of the subject, and as a statement in which I fully concur.) 



