520 MONOGEAFIIS OP NORTH AMERICAN RODENTIA. 



in 1857, and by myself in the present instance, is really (lie C. parvus of 

 Peale. Professor Baird spoke guardedly in the matter, although he did not 

 formally query his citations, as I have done, and I find myself equally in 

 doubt. Nor do I see how the point is to be determined. For Peale's type, 

 having been lost or mislaid, is not at hand to testify; and Peale's description, 

 though elaborately detailed, will be found to consist entirely of supergencric 

 characters, shared by all the species of Perognathus and Cricetodipus, except- 

 ing the phrase "color above sepia-brown", which is applicable to none of the 

 species known to me. The dimensions assigned agree exactly with those of 

 the animal defined in this article; but they are equally applicable to a very 

 young Perognathus. In fine, there is no proof that Peale's genus and species 

 were not based upon a young Perognathus — possibly monticola. Therefore, 

 while glad to concede that the probabilities are the other way, I think it safest 

 to query the citation of Peale's animal and the compiled references that go 

 with it; and I rest upon the Perognathus parvus of Baird, about which there 

 is no uncertainty. LeConte's P. parvus, as I have already shown, is doubt- 

 less based upon a very young example of P. penicillatus. 



Baird's animal, from King's Eiver, Cal., is very immature, as shown by 

 the state of the teeth, though nearly or quite full grown. It curiously resem- 

 bles a very young P. penicillatus (like LeConte's specimen for instance) ; and, 

 indeed, Professor Baird was led, by its immaturity and defective state of 

 preservation, to suggest that it might not impossibly belong to P. penicillatus, 

 though he proceeded to make it the basis of his P. parvus. It is, however, 

 unquestionably a Cricetodipus, as I can affirm without qualification from 

 inspection of the skull, which clearly shows the bulge of the mastoid back of 

 an occipital emargination and other cranial characters diagnostic of Cricetodi- 

 pus, to say nothing of the hairy soles and unlobed antitragus. I therefore 

 accept the species as first clearly defined by Baird, without necessarily involv- 

 ing the question by including the doubtful animal of Peale. 



As already suggested, the chances are that Baird was right in identifying 

 his species with that of Peale, so that the name Cricetodipus parvus will prob- 

 ably stand. But should the contrary prove to be the case, and Cricetodipus, 

 Peale, 1848, be conclusively shown to be a synonym of Perognathus, Maxim., 

 1839, a new name, generic and specific, will be required for the subject of 

 the present article. The name Otognosis would be appropriate, in allusion 

 to the facility with which the species may be distinguished from those of 



