Considering the large number of specimens of _noveboracensis_ which are available in comparison with the few of _occisor_ it is not surprising that some _noveboracensis_ should be found which exceed in size those of _occisor_. This is the case as regards the basilar length of a very old male, no. 96518, U. S. Nat. Mus., from Lunenburg, Massachusetts. Also, the skull is actually broader than any of those of _occisor_. However, this specimen is much older than any _occisor_ examined. In a female, no. 4260, Mus. Comp. Zoöl., from Liberty Hill, Connecticut, the skull is longer (but narrower) than in either of the two available females of _occisor_. The average differences pointed out above which characterize this extreme northern population of _noveboracensis_-like weasel in comparison with true _noveboracensis_ without much question are geographic variations. Whether or not these variations are of a degree sufficient to warrant nomenclatural recognition is debatable. With equally scanty material from other regions I have not named variations seemingly as great as those shown by _occisor_. The paucity of material of _occisor_ is a handicap in making a decision in this instance. Each of the adult and subadult specimens, except the one from Perry, shows malformation resulting from the infestation of the frontal sinuses with parasites. _Specimens examined._--Total number, 18, listed by counties from west to east and unless otherwise indicated in the Museum of Comparative Zoölogy. =Maine.= _Oxford County_: South Andover, 2 (Boston Soc. Nat. Hist.); Umbagog Lake, 1. _Franklin County_: Seven Pd. Township, 1. _Piscataquis County_: Grenville, [= Greenville?], 1. _Hancock County_: Bucksport, 10. _Washington County_: 3rd Mopang Lake, 1 (Acad. Nat. Sci. Phila.); Perry, 1 (Boston Soc. Nat. Hist.). _County_ in question: Moosehead Lake, 1. =Mustela frenata primulina= Jackson Long-tailed Weasel Plates 16, 17, 18, 31, 32 and 33 _Mustela primulina_ Jackson, Proc. Biol. Soc. Washington, 26:123, May 21, 1913. _Putorius noveboracensis_, Baird, Mamm. N. Amer., p. 166, 1858 (part). _Mustela longicauda longicauda_, Dice, Journ. Mamm., 4:108, May 9, 1923. _Mustela longicauda primulina_, Linsdale, Journ. Mamm., 9:141, May 9, 1928. _Mustela frenata primulina_, Hall, Carnegie Instit. Washington Publ. 473:104, November 20, 1936. _Mustela frenata_, Leopold and Hall, Journ. Mamm., 26:143, July 19, 1945. _Type._--Male?, young, skull and skin; no. 168006, U. S. Nat. Mus., Biol. Surv. Coll.; 5 miles northeast of Avilla, Jasper County, Missouri; May 11, 1905; obtained by Hartley H. T. Jackson; original no. 7869X.