POSITION IN ANIMAL KINGDOM. 41 



order [Myomorplia) , in which it constitutes the second 

 family, and the third in the general series from the 

 first. This arrangement appears merely to transfer 

 without obviating the difficulty, and tends to compli- 

 cate rather than simplify the question. 



Baird introduces into the family Castoridse the 

 genus Aplodontia, consisting of a single species found 

 in Ore2;on, and confined to the Northwest Coast. In 

 some features of the teeth and skull it resembles 

 Castor, and in other particulars affiliates equally well 

 with other genera of rodents. He then, having 

 placed the Sciuridse, as other zoologists have done, in 

 the front rank of the rodent order, attaches the 

 genera Aplodontia, Castor, and Castoroides to this group 

 as a sub-family, expressing, however, a doubt as to the 

 propriety of the arrangement in the following lan- 

 guage : " There has been of late a decided tendency 

 to place them near or among the Sciuridse. In this 

 view I am disposed to concur, although there still 

 remains the question, whether the two are not typical 

 of as many different sub-families, themselves forming 

 a family of full rank."^ 



Although unqualified to offer any solution of this 

 problem, it appears to me plain that the greater rela- 



videtur, subordinum valorem exhibentes manifestat : Glires, Sciu- 

 roniorphos, Myomorphos, Hystrichomorphos, et Lagomorphos, 

 quorum quidem siugulorum fundamenta generalia genera Sciurus, 

 Mus. Hystrix, et Lepus omnibus nota declarari possunt. Typi 

 quatuor modo dici vero notis constanter diversis minime disjunct! 

 apparent, sed notarum coramunium formarumque intermediarum 

 ope series potius satis harmonice in unitatem conjunctas ofFerunt." 

 — Memoires de Academie Imperiale des Sciences de St. Peters- 

 bourg. Sixth series. Sciences Naturelles, tome vii. 292. 

 ^ Explorations for a Railroad Route, etc., viii. 350. 



