An adult female, no. 426a, Iowa State College, from Barnum, in the brown winter coat, agrees with primulina except that the orbitonasal length of the skull is more as in spadix and the presence of some light color on the lower part of the hind legs suggests spadix. The skull only, no. 440a, Iowa State College, labeled merely Webster County, Iowa, is almost a duplicate of no. 426a. A subadult male, no. 427a, Iowa State College, from Moorland, Iowa, only about six miles southeast of Barnum, likewise is indistinguishable from primulina except for having a white winter coat and in being relatively broad in the mastoidal region. Nevertheless, both of these animals are here referred to spadix because the average of specimens from this general area is nearer that of spadix. No. 497a, Iowa State College, an adult female in white winter pelage, from Ames, approaches primulina in the narrow rostrum and smaller teeth but otherwise approaches or even agrees with spadix.
Two adult males, without external measurements, from Pilot Mound, Iowa, have skulls quite like males of longicauda from Alberta. The only approach noted to eastern forms is the restricted color of the underparts on no. 2856, Coe College, which has a brown winter coat. The color of the underparts is not extended so far out on the feet as in longicauda. Also the tympanic bullae of this specimen are a trifle narrower. The other male, no. 2652, is in the white winter coat. The one female from the same place, no. 2660, Coe College, in brown winter pelage, has a skull notably unlike that of longicauda or spadix; the skull is narrower and practically indistinguishable from that of the largest female skull of primulina available from Lawrence, Kansas, save that the tooth-row is much longer. The color pattern also agrees with that of primulina or noveboracensis in that the color of the underparts extends only as far as the knee on the hind legs and is narrow on the belly. Nevertheless, another adult female, no. 120a from Amaqua Township, some 6 miles southwest of Pilot Mound, is in all respects typical of spadix. This is the more remarkable because another comparable specimen from less than 20 miles to the southwest in Worth Township is equally typical of primulina.
Two young females from Chester, Iowa, nos. 2656 and 2874/2873, Coe College, have skulls larger than those of corresponding age of primulina or noveboracensis. The color is as in spadix. The color pattern of the underparts also is as in spadix or longicauda except that the width of the area of light color on the belly is restricted somewhat although not so much as in noveboracensis or primulina. Of four males from the same place, also in the collection of Coe College, no. A2874 is a white skin only and does not provide diagnostic characters. The three other males, each in summer pelage, are marked and colored as are the two females from the same place except that male no. 2861 has the color of the underparts so much attenuated on the hind legs that it barely, uninterruptedly, extends to the feet. No. 2658 is young, or perhaps barely subadult. The skull is large and referable to spadix. The two adults, nos. 2861 and 2657, differ cranially from typical (Elk River, Minn.) spadix only in being slightly narrower across the mastoids and in having the bullae a little narrower. In these departures they show some approach to primulina and to noveboracensis. Another male, subadult, no. 2867, Coe College, from Decorah, which has acquired half of the white winter coat, agrees with the males from Chester except that the preorbital part of the skull is shortened much as in some specimens of primulina.
From Lansing, in extreme northeastern Iowa, a large subadult male, no. 2864, Coe College, of 453 mm. in total length and half through with acquiring the white winter coat, agrees with the males previously described from Chester except in having the palate narrower as in noveboracensis. The adult female available from Lansing, no. 2863/2862, Coe College, in white winter pelage except for the top of the head, although a large skin, has a skull smaller than that of any spadix or longicauda and of about the same size as that of no. 3838, Univ. Kansas Mus. Nat. Hist., of primulina, from Lawrence, Kansas, except that the skull of no. 2863/2862 is much narrower across the mastoids. This specimen, then, shows approach to noveboracensis in narrowness of the mastoidal region, to primulina in other respects and to spadix.
Many of these instructive specimens from Iowa, made available to the present writer by Mr. W. F. Kubichek, were brought together at the Coe College Museum by the late B. H. Bailey. Most of them were obtained from trappers who did not supply the conventional external measurements taken in the flesh. Even though these are lacking, the specimens clearly show that actual intergradation occurs where the ranges of M. f. longicauda, spadix, noveboracensis and primulina meet.
The dark color of the upper parts, restriction of the color of the underparts on the ankles with the result that the color reaches the toes in interrupted fashion, and large skull, of no. 18912 of the Museum of the University of South Dakota, from Roberts County, South Dakota, clearly place this specimen with spadix, rather than with longicauda. Likewise, male, subadult, no. 11376, Univ. South Dakota, from Clay County, South Dakota, is referable to spadix. Although without external measurements, the specimen obviously is large. The patch of summer pelage on its head and neck is darker than the summer pelage of longicauda, and the orbitonasal length is greater than the length of the tympanic bullae; all these features are characters of spadix. The adult male from Fort Sisseton, South Dakota, no. 188407, United States National Museum, figured by Merriam (1896, p. 20, figs. 7-9), is almost exactly intermediate between longicauda and spadix, although here referred to the latter.
Five specimens, nos. 147375, 147432, 147762, 148720 and 148721, U. S. Nat. Mus., including 3 skulls only from Beemer, Cuming County, Nebraska, are intergrades between M. f. longicauda, M. f. primulina and M. f. spadix. One skin is in white winter pelage and the other, a female, is in summer pelage which in coloration and color pattern agrees with that of spadix. External measurements of the male agree with those of longicauda. Measurements of the female agree with those of spadix except that the tail is shorter as in primulina. The skulls are as long as in longicauda but are more slender than in either longicauda or spadix although nearer the latter in this respect. In dorsal aspect, the skulls especially posteriorly to the orbital region, resemble primulina. All points considered, the animals seem best referred to spadix.
Although the degree of development of certain morphological features has been settled upon as indicative of the race spadix, some doubt remains as to where the western boundary of its range should be shown. This results from the fact that color has been taken into account as one diagnostic feature and this feature is lacking in the white winter specimens which, from the following places, are all that are available: Kittson County, Minnesota; Moorhead, Minnesota; Casselton and Valley City in North Dakota; Armour, South Dakota and Clay County, South Dakota. In summary, more specimens in the summer coat will be required to establish definitely the boundary between the ranges of longicauda and spadix.