median strip of grizzled gray. It is true that specimens from Miniatitlan are darker than those from Altamira, but this seems not to be significant taxonomically, because examination of series from other localities provides no evidence of geographic variation in color except, possibly, in the frequency of melanism. A series of 13 specimens (Univ. Kansas) from 7 and 8 km. WNW Potrero, Veracruz, for example, is quite as dark as topotypes of S. a. hypopyrrhus from Miniatitlan, although the localities of capture are approximately in the center of the geographic range of S. a. aureogaster. In short, there seems to be no way to distinguish S. a. hypopyrrhus from S. a. aureogaster on the basis of color. An unusual amount of variation exists, but it seems to occur at random. Fixing type localities of the two subspecies at the places of origin of certain specimens which in color fit the original descriptions is meaningless because selected specimens or series from almost any place in the geographic range of the species would qualify as approximate color-duplicates of the types.

My findings agree with those of Nelson in that skulls from Miniatitlan average longer and narrower than those from Altamira, but this seems not to be significant taxonomically because the series from Altamira is, to judge from the material I have seen, somewhat shorter and broader cranially than is "average" for the alleged subspecies S. a. aureogaster. For example, series from Metlaltoyuca in Puebla, 3 km. E Axtla in San Luis Potosí, 8 km. NW Potrero and 20 km. NW Piedras Negras in Veracruz, although obtained from localities well within the geographic range of S. a. aureogaster (as outlined by Nelson), all more closely resemble the "topotypes" of S. a. hypopyrrhus in cranial measurements than they do "topotypes" of S. a. aureogaster. Conversely, specimens from that part of the range of S. a. hypopyrrhus most remote from the range of S. a. aureogaster (Montecristo, La Venta, and Teapa, all in Tabasco) more closely approximate the Altamiran series in cranial size and proportions than they do the Miniatitlan material. Therefore, my data contradict the statement of Nelson (loc. cit.) that the skulls of S. a. hypopyrrhus are larger but proportionately narrower than those of S. a. aureogaster. The constriction of the auditory bullae alluded to by Nelson as being present in S. a. hypopyrrhus is also present in S. a. aureogaster, occurring in both subspecies in varying degrees without correlation with geographic distribution.

Actually, the only concrete evidence of geographic variation that I can detect in these animals is a slight increase southwardly in the frequency and degree of melanism, a kind of variation that is unworthy of taxonomic recognition in this species. It seems best, then, to regard the name Sciurus aureogaster hypopyrrhus Wagler as a synonym of Sciurus aureogaster aureogaster F. Cuvier.

Nelson (op. cit.:45) stated that S. a. frumentor "Differs strikingly from typical aureogaster in having well-marked nuchal and rump patches of yellowish brown or rufous brown; the underparts gray or gray washed with rufous; tail heavier and more bushy; pelage softer.... Skull indistinguishable from that of typical aureogaster." I have examined 22 specimens from Jico, 7 from Las Vigas (the type locality), and one from 3 km. E Las Vigas, all in Veracruz. These include the type and paratypes of S. a. frumentor. Part (probably 7 specimens) of the series from Jico was referred by Nelson (op. cit.:46) to S. a. frumentor and he thought, or knew, these specimens to have been taken above Jico. The remaining specimens labelled as from Jico were referred to S. a. aureogaster. I am unable to find fault with the characterization of S. a. frumentor insofar as color or skull are concerned. I cannot verify