Part 3

9. Height of keel 1/7 of length of tip; angle formed by tip and shaft distinct Eutamias alpinus, p. 616

9'. Height of keel at least 1/5 of length of tip; angle formed by tip and shaft poorly defined.

10. Height of keel 1/3 of length of tip; angle formed by tip and shaft 140° Eutamias dorsalis, p. 620

10'. Height of keel 1/5 of length of tip; angle formed by tip and shaft 130° or less.

11. Tip more than 29 per cent of length of shaft. Eutamias amoenus, p. 619

11'. Tip less than 28 per cent of length of shaft. Eutamias minimus, p. 617

7'. Base widened and dorsoventrally thickened. Eutamias townsendii, p. 618

5'. Shaft thick; shaft more than .25 mm. in diameter at widest point.

12. Length of shaft less than 3.00 mm.; length of tip less than 1.10 mm. Eutamias quadrivittatus hopiensis, p. 622

12'. Length of shaft more than 3.10 mm.; length of tip more than 1.15 mm.

13. Tip less than 28 per cent of length of shaft. Eutamias quadrimaculatus, p. 624

13'. Tip more than 29 per cent of length of shaft.

14. Angle formed by tip and shaft more than 140°; ridges on either side of tip indistinct. Eutamias cinereicollis, p. 624

14'. Angle formed by tip and shaft less than 135°; ridges on either side of tip distinct.

15. Shaft less than 3.65 mm. in length, and .55 mm. or less in diameter at widest point. Eutamias quadrivittatus quadrivittatus, p. 621

15'. Shaft usually more than 3.65 mm. in length, but when shorter, diameter is .60 mm. or more at widest point.

16. Diameter of shaft at widest point less than .58 mm.; tip less than 35 per cent of length of shaft. Eutamias ruficaudus ruficaudus, p. 622

16'. Diameter of shaft at widest point more than .65 mm.; tip more than 40 per cent of length of shaft. Eutamias ruficaudus simulans, p. 623

ACCOUNTS BY SPECIES

#Eutamias alpinus# (Merriam)

Figure 1

Pelage silky; tail bright orange beneath; markings relatively obscure; size small; skull broad, flattened, and large in proportion to body.

Baculum: Shaft thin; keel low, 1/7 of length of tip; tip 39 per cent of length of shaft; angle formed by tip and shaft 135°; distal 1/3 of shaft slightly compressed laterally; base slightly wider than shaft; shaft short, 2.17 mm.

Differs from E. speciosus, E. panamintinus, E. umbrinus, E. palmeri, and E. bulleri, in base not markedly widened, and shaft thinner; from E. quadrivittatus, E. ruficaudus, E. cinereicollis, and E. quadrimaculatus, in shaft thinner, baculum shorter; from E. townsendii, in base not dorsoventrally thickened, base not so widened; from E. sonomae, in ridges on either side of tip not enlarged, base not dorsoventrally thickened; from E. amoenus, E. minimus, and E. dorsalis, in keel lower, angle formed by tip and shaft more distinct; from E. merriami, in baculum markedly shorter, base not incised dorsally.

Specimen examined: One from Big Cottonwood Meadows, S of Mount Whitney, 10,000 ft., Inyo Co., California (CN).

#Eutamias minimus# (Bachman)

Figure 2

Coloration varying from light to dark depending on subspecies; size small to medium; rostrum short and stout.