J. A. Allen (Bull. Amer. Mus. Nat. Hist., 5:184, August 18, 1893) listed as Perodipus agilis a specimen (6306/4941 AMNH) from Valladares, Baja California. Subspecies of this species were subsequently named without mentioning this specimen that, on geographic grounds, might be either D. a. martirensis or D. a. simulans. Certain measurements of the specimen are as follows: Total length, 288; length of tail, 171; length of hind foot (dry), 41.0; greatest length of skull, 39.5; width of maxillary arch at middle, 4.5. The long tail and wide (4.5) maxillary arch are characteristic of Dipodomys agilis simulans and constitute the basis for identifying the specimen as of that subspecies.
Baiomys taylori analogus Osgood
The geographic range currently assigned to Baiomys taylori paulus (J. A. Allen) is separated in two parts by the geographic range assigned to B. t. analogus. The southern, separated part of the range of B. t. paulus rests wholly on ten specimens from Colima, Colima, identified as B. t. paulus by Osgood in his "Revision of the mice of the American genus Peromyscus" (N. Amer. Fauna, 28, April 17, 1909) where (p. 255) he places as a synonym of Peromyscus taylori paulus J. A. Allen, 1903, Peromyscus allex Osgood, 1904. The later name was based on these ten specimens (33422/45445-33427/45450, 33429/45452, 33432/45455, and 33435/45458 BS) from Colima. Osgood had a choice of synonymizing P. allex under P. paulus or P. t. analogus. According to Osgood's concept, analogus was blackish and large; allex was grayish and small; and paulus was fawn colored and intermediate in size. The more nearly equal size of paulus and allex probably influenced Osgood in making his choice. After examining the original materials we think there is more to recommend the alternate choice. For example, two topotypes of equal age of the same sex of allex (33424/45447) and analogus (120264 BS) are of almost the same size and, respectively, measure as follows: Total length, 107, 108; length of tail, 42, 45; length of hind foot (measured dry), 13.1, 12.8; greatest length of skull, 17.6, 17.7; zygomatic breadth, 9.3, 9.2. Although analogus does average darker, a topotype, No. 120267 BS, from Zamora, is indistinguishable from several of the topotypes of allex. Consequently, we arrange Peromyscus allex Osgood as a synonym of Baiomys taylori analogus (Osgood) 1909 and refer the specimens from Colima to the latter.
Peromyscus eremicus eremicus (Baird)
Osgood (N. Amer. Fauna, 28:242, April 17, 1909) listed a specimen of this subspecies from Sierra Encarnación, Nuevo Leon. A specimen, No. 79614 BS, of this species was obtained on July 31, 1896, at Sierra Encarnación, Coahuila, by Nelson and Goldman. We know of no specimens of this subspecies from Sierra Encarnación, Nuevo Leon, and assume that Osgood referred to the Coahuilan specimen. Further support for this assumption is Osgood's (loc. cit.) note that the Sierra Encarnación specimen is aberrant and, to our eye, so is No. 79614 from Coahuila.
Peromyscus merriami merriami Mearns
Osgood (N. Amer. Fauna, 28:239, April 17, 1909) placed P. merriami in synonymy under Peromyscus eremicus eremicus (Baird). Because Seth B. Benson, and subsequently the late Wilfred H. Osgood, told one of us (Hall) that Peromyscus merriami was specifically distinct from Peromyscus eremicus eremicus, we have examined the specimens from Sonoyta, Sonora, and Quitobaquita, Arizona, referred by Mearns (Bull. U. S. Nat. Mus., 56:434-435, and 444, April 13, 1907) to P. e. eremicus and P. merriami, respectively. We perceive the differences that Mearns (loc. cit.) described and recognize P. merriami as a species separate from P. eremicus.
Also we have compared the type and one topotype of Peromyscus goldmani Osgood with the holotype and referred specimens mentioned above, of P. merriami, and feel that the two kinds are no more than subspecifically distinct. Accordingly, P. goldmani should stand as Peromyscus merriami goldmani. This arrangement is made with the knowledge that Burt (Misc. Publ. Mus. Zool., Univ. Michigan, 39:56, February 15, 1938) arranged P. goldmani as a synonym of Peromyscus eremicus.
Peromyscus truei preblei Bailey
Osgood (N. Amer. Fauna, 28: 171, April 17, 1909) listed two specimens from Crooked River, 25 miles southeast of Prineville, Oregon, as Peromyscus truei gilberti with the notation "approaching truei?" Subsequently, Bailey (N. Amer. Fauna, 55: 188, August 29, 1936) named Peromyscus truei preblei with type locality at Crooked River, 20 miles southeast of Prineville, a place from which Bailey had two specimens. We think the specimens recorded by the two authors are the same, and, according to the specimen labels, were placed correctly as to locality by Bailey. Our reasons are as follows: (a) The specimens mentioned by Bailey were presumably available to Osgood, but Osgood made no mention of specimens from "20 miles southeast of Prineville," (b) we find no specimens nor other records pertaining thereto, of Peromyscus truei from the locality given by Osgood, (c) Osgood indicated that the specimens he saw were not typical of P. t. gilberti and (d) P. m. gilberti, geographically the nearest subspecies, is recorded otherwise no closer to Prineville than Grants Pass, approximately 175 miles southwest in southwestern Oregon.