556 MONOGRAPHS OF NORTH AMERICAN RODENTIA. 



consideration of external form, upon which a genus Haplodon may be 

 properly based. In the account of the species which is to follow, much of 

 the structure of the animal is given in detail, without reference to the sys- 

 tematic significance of any of the features described. 



The genus u Aplodontid 1 ' 1 was established by Richardson in 1829, and, 

 with varying orthography, has since been universally employed. Nor is it 

 necessary to supersede it by Anisonyx of Rafinesque, 1817. This generic 

 term, besides arising in a misunderstanding, was based upon the "Burrowing 

 Squirrel" of Lewis and Clarke, and is equivalent to Cynomys, of same author 

 and date. It therefore becomes a synonym of Cynomys, as the type species, 

 "■Anisonyx brachiura v , also is of Cynomys columbianus (Ord). Rafinesque, 

 however, added to his genus Anisonyx a second species, A. rvfus, based ex- 

 clusively upon the Sewellel of Lewis and Clarke, which causes Anisonyx to 

 be partly synonymous with the subsequent "Aplodontia" of Richardson. 



The construction of the generic word has apparently given trouble, 

 though there need have been none, had the rules for the formation of com- 

 pounds from the Greek been duly considered. While some latitude is allow- 

 able in such cases, unwarrantable liberties have been taken with this word 

 The etymology is dirXoos (contr. a7rXov?), simplex, simple, and odovs, dens, 

 tooth. The original form, Aplodontid, is clearly wrong in ignoring the aspi- 

 ration of the initial Alpha, and is further modified arbitrarily by the suffixed 

 syllables. As to the mode of joining the two words, in which three Omicrons 

 come together, it may be observed: that the latter o in axXooS would, of 

 course, suffer elision before the initial vowel of cdov?; and then the former 

 o, still coming before a vowel, would either be separated by a diaeresis over 

 the second o, or else be contracted with it into ov; so that the word might 

 be written, with propriety, Haploodon or Haphudon, the latter perhaps 

 being preferable, especially in view of the contracted form a7rXov?, in 

 which the original is also found. But euphony has rightly so much to 

 do with these formations that, the former o in dnXooi, as well as the 

 hitter, may be struck out before the 6 of odovs (just as the latter o may 

 be omitted before a consonant, contrary to general rule, as in d/rXor?/?, 

 compounded of a7rX6o? and the abstract termination 77?, or in a7rXoo~if>?}- 

 /igov), and the word be properly written Haplodon, the form I have 

 adopted. In any event, Apludoniia and Apluodontia are inadmissible, 

 and Hapludon is objectionable from excessive contraction. In strictness, 



