A New Pocket Mouse (Genus Perognathus) from Kansas — Inside the Classic

Evidence and Method in a Four-Page Description

The paper's structure is typical for a taxonomic note. It opens with a brief rationale: while studying Kansas mammals, Cockrum examined a series of Perognathus flavus from western Kansas and found they belonged to an undescribed subspecies. The core of the work is the formal description, which includes a type specimen (a female adult, skin and skull, catalog number 11716), a diagnosis, measurements, and comparisons with three named subspecies: P. f. flavus, P. f. piperi, and P. f. sanluisi. The comparisons rely on cranial measurements (e.g., frontonasal length, mastoidal breadth, interparietal width) and color descriptions using Ridgway's 1912 color standards. The language is precise and technical: 'upper parts between Pinkish Buff and Cinnamon-Buff, sparsely mixed with black hairs.' No speculation about behavior, habitat, or evolutionary significance appears.

Color and Skull: The Key Differentiators

Cockrum's diagnosis emphasizes two main traits: size and color. The new subspecies is described as 'large' for the species, with a 'much enlarged' frontonasal and mastoidal region and a 'transversely narrow' interparietal. Color is given in careful detail: the upper parts are light, between Pinkish Buff and Cinnamon-Buff, with sparse black hairs, producing an effect at eight feet of 'between Clay Color and Tawny-Olive.' The lateral line is 'well marked,' and the underparts are white. In comparisons, bunkeri is consistently described as 'more buffy' and 'lighter' than related forms, with fewer black hairs dorsally. The paper does not explain why these differences matter; it simply records them as evidence for the new taxon.

What the Excerpts Do Not Reveal

The available text is incomplete—only the first page of the paper is included, plus the Project Gutenberg boilerplate. The full paper likely contains a table of measurements, a distribution map, and a list of specimens examined, but these are absent here. The excerpts also cut off before any discussion of the subspecies' range or habitat. The catalog subjects imply a broader treatment of Kansas mammals, but the paper is a narrow taxonomic contribution. Readers should not expect an overview of pocket mouse biology or Kansas fauna. The work is best understood as a primary source in systematic mammalogy, useful for those tracking taxonomic history or the work of E. Lendell Cockrum.

This paper is a specimen-level taxonomic description, not a general natural history. Readers interested in the methods of mid-20th-century mammalogy or the history of Kansas faunal studies will find it a clear example of the genre. For those seeking broader context, Cockrum's other publications or the University of Kansas Museum of Natural History series may be more illuminating. The excerpts here are sufficient to observe the paper's structure and evidentiary style, but the full text is needed for complete data.

Reading the precise cranial measurements in this 1951 pocket mouse paper, I remembered my grandfather's field notebook—similar quiet devotion to tiny differences. That same patient wonder surfaced in Useful Knowledge: Volume 3. Animals Or, a familiar account of the various productions of nature — Context and Discussion, where animals appeared not as abstractions but as particular creatures, each with its own small story waiting to be noticed.