Remarks.—The two adult males, nos. 286 and 289 from Saook Bay, provide convincing evidence of the existence of a distinct race of weasel on Baranof Island. Three other young specimens, almost subadult, from the same place are labeled as males although the basilar lengths of these skulls are only 35.5, 35.9 and 37.3 millimeters as against 39.6 and 40.5 in the two adult males. The difference in size is too great to be age-variation. The fact that 3 are definitely of one category and 2 of the other makes it doubtful that individual variation accounts for the differences. The small size of these 3 specimens and the fact that in each the anterior margin of the tympanic bulla is flush with the squamosal rather than protruded from the braincase, suggests that the three are females. If they are females, the amount of secondary sexual variation is rather less than would be expected by analogy with the amount obtaining in alascensis on the mainland and in salva on Admiralty Island. Another possibility that I can not disprove is that two stocks of weasels persist on Baranof Island, the two larger specimens being descendants of the stock which first became established on the island and the three smaller specimens being descendants of an individual ermine, or of ermines, that were rafted or otherwise transported to the island at a considerably later date. Assuming for the moment that there are two stocks, it must be admitted that each one differs from any stock known from elsewhere. Therefore, each stock would be presumed to have been long resident on the island. But—two stocks as closely related as the two in question would not be expected to persist for long in an area as small as that of Baranof Island because competition would give one the ascendancy. Therefore, the first suggestion, namely that the three smaller animals are really females, seems the more probable. The feasible way to clear up the present uncertainty is, of course, to obtain additional specimens, carefully labeled as to sex. Yet another reason why additional collecting is desirable in this area is to ascertain whether there is subspecific differentiation between the ermines of Baranof and Chichagof islands. The one specimen available from the latter island, although in general like the three smaller animals from Baranof Island, differs in the fuller (less scooped out) medial side of the tympanic bulla and to a slight degree in each of some other features. This specimen from Chichagof Island is labeled as a male also.
Specimens examined.—Total number, 6, arranged by localities from north to south, and in the Museum of Vertebrate Zoölogy, University of California.
Alaska. Chichagof Island, Freshwater Bay, 1. Baranof Island, Saook Bay, 5.
Mustela erminea celenda Hall
Ermine
Mustela erminea celenda Hall, Proc. Biol. Soc. Washington, 57:38, June 28, 1944; Hall, Journ. Mamm., 26:181, July 19, 1945.
Type.—Male, adult, skull and skin; no. 130987, U. S. Nat. Mus., Biol. Surv. Coll.; Kasaan Bay, Prince of Wales Island, Alaska; June 16, 1903; obtained by Cyrus Catt; original no. 4407X.
The skull has a piece 1.5 mm. long broken out of the left zygomatic arch. P2 is absent on both sides. The right I1, and the left I1 and I2 are missing. The skin, in summer pelage, is fairly well made. A scrotal pouch attests to the correctness of the sex recorded on the label. The rostral part of the skull is smaller than in average-sized males of corresponding age.
Range.—Prince of Wales, Dall, and Long islands, Alaska. See figures [25], [26] on pages [95], [134].
Characters for ready recognition (only males known).—Differs from M. e. alascensis and initis in chest mostly covered by brown patch, not white, and breadth of rostrum measured across lacrimal processes more than a third of basilar length, which cranial character serves to distinguish also salva; from M. e. seclusa in zygomatic breadth less than distance between last upper molar and jugular foramen; from M. e. haidarum in chest white (not mostly covered by brown patch), proximal two-thirds of underside of tail colored like upper parts rather than underparts, basilar length more than 38.2 mm.
Description.—Size.—Male: Seven adults and subadults from Prince of Wales Island, yield average and extreme measurements as follows: Total length, 286 (277-304); length of tail, 77 (74-85); length of hind foot, 36 (35.5-40.5).
Female: No specimen available.
Color.—As described in Mustela erminea richardsonii except that upper parts about tone 3 of dark Chocolate Brown of Oberthür and Dauthenay, pl. 342; lower throat and chest covered by a large patch of same color as upper parts; color of underparts extending to toes but in interrupted fashion on both fore- and hind-feet; least width of color of underparts averaging, in four males from Prince of Wales Island, 41 (38-49) per cent of greatest width of color of upper parts. Black tip of tail averaging, in 8 males in winter pelage, 65 (59-78) mm. which is 84 (69-92) per cent of length of tail-vertebrae.
From its geographic neighbors alascensis and initis, celenda differs in darker color of upper parts, presence rather than absence of patch of dark color on lower throat and chest, and longer black tip on tail. From haidarum, celenda differs in darker color of upper parts, presence rather than absence of patch of dark color on lower throat and chest, narrower light-colored under parts, black tip of tail averaging less rather than more than nine-tenths of length of tail-vertebrae and ventral face of tail colored like upper parts rather than like underparts.
Skull.—Male (illustrated by 5 adults): See measurements and plates [5]-[7]. As described in Mustela erminea richardsonii except that: Weight, 2.3 (2.2-2.5) grams; basilar length, 39.5 (38.9-40.7) mm.; length of tooth-rows more than length of tympanic bulla; breadth of rostrum measured across lacrimal processes more than a third of basilar length; interorbital breadth more than distance between glenoid fossa and posterior border of external auditory meatus; zygomatic breadth more or less than (about equal to) distance between last upper molar and jugular foramen.
Female.—Complete skull of adult unavailable.
Differences from richardsonii are indicated in the formal description just given. Additional to differences therein noted, celenda differs from initis in larger interorbital and preorbital parts of the skull although dimensions of other parts of the skull and the teeth are about the same or even less. From salva, celenda differs in larger average size in every measurement taken, except for the inner moiety of M1 which is about the same. The skull of celenda is 35 per cent heavier. In relation to the basilar length the skull of celenda is wider, especially in the interorbital and preorbital regions. In comparison with alascensis the tympanic bullae are of approximately the same length; otherwise essentially the same differences obtain as are noted in comparison with salva and the zygomatic breadth is relatively more in celenda. From seclusa, in which the teeth are of comparable size, celenda differs in that every cranial measurement is more and the skull is 28 per cent heavier. Because the skull of celenda is so much longer, its dimensions in other planes are less in relation to the length than in seclusa. M. e. celenda is larger in every part measured than haidarum, 21 per cent heavier, and in relation to the basilar length the interorbital, and preorbital, parts of the skull are smaller, the braincase is shallower, and the skull is relatively wider across the zygomata and mastoid processes. In comparison with kadiacensis, differences are: 26 per cent lighter, skull shorter; in relation to the basilar length, braincase shallower as measured at the anterior end of the basioccipital, tooth-rows shorter but orbitonasal length more. In comparison with arctica all parts measured of the teeth and skull of celenda are smaller and its skull is 34 per cent lighter. In relation to the basilar length, the interorbital breadth of celenda is only slightly less but its skull is narrower across the rostrum and zygomata, the tooth-rows are shorter, and the braincase is shallower.