418 



SCIENCE. 



[N. S. Vol. II. No. 39. 



single species, Neotoma mexioana Baird, and the 

 extraordinary opinion is expressed tliat N. albi- 

 gula Hartley ' is not separable from N. mexi- 

 cana.^ Here, as in a previous paper, the 

 author shows himself hopelessly at sea. Neo- 

 toma alhigula and N. mexicana not only inhabit 

 different life zones but belong to different groups 

 or subdivisions of the genus ! 



The Arizona form of the Plains Prairie Dog 

 is given as a distinct species, but anyone who 

 will take the trouble to compare it with speci- 

 mens from New Mexico and Texas will see that 

 at most it is only a subspecies. On the other 

 hand, the long-eared Arizona Jack Cottontail is 

 given as a subspecies, though very distinct from 

 any other known rabbit. 



By curious lapse of memory the round-tailed 

 spermophile {Spermophilus tereticaudus) is al- 

 lowed to remain in the subgenus Ictidomys — a 

 subgenus erected by Dr. Allen in 1877 for 

 species with narrow elongate skulls. The 

 species originally referred to it are tereticaudus, 

 tridecemlineatiis suLdfranklini. S. tereticaudiis has 

 one of the shortest and broadest skulls known 

 in the whole genus Spermophilus, but, probably 

 ,by accidental transposition of skulls, it was de- 

 scribed by Dr. Allen as long and slender. When 

 his attention was called to the matter he very 

 properly withdrew tereticaudus from the group 

 and suggested that 13-lineatus be taken as the 

 type of Ictidomys, no type having been desig- 

 nated in the original description. But in the 

 present paper the short skulled tereticaudus is 

 again placed in Ictidomys ! 



Say's ground squirrel {Spermophilus lateralis) 

 is persistently referred to the genus Tamias — a 

 genus with which it has no affinity whatever 

 and to which it bears only the most superficial 

 resemblance. 



With respect to the white-footed mice of the 

 Peromyscug sonoriensis group, it is not likely 

 that the last word has been said. 



The generic name Adelonycterifi, adopted from 

 Harrison Allen for the large Brown Bat, has no 

 claim for recognition, being antedated by at 

 least two names of equal pertinency. 



The specific name now in current use for the 

 Mountain Sheep {Ovis canadensis Shaw) is re- 

 placed by O. cervina Desm. without apparent 

 reason. Both names were published in 1804, 



but there is no e\'idenee that cervina antedates 

 canadensis. In the absence of positive proof of 

 priority such changes are most unfortunate and 

 not likely to stand. 



Passing from technical matters to the sub- 

 stance of the paper, one finds much of interest 

 and numerous previously unpublished records. 

 And it is gratifying to learn that elk still in- 

 habit the White Mountains on the boundary 

 between Arizona and New Mexico, where one 

 was shot August 10, 1894. It is to be regretted 

 that the specimen was not preserved. 



C. H. M. 



La sensibility de fceil aux coleurs spectrales. M. 



Parinaud. Revue Scientifique, Ser. 4, T. 3, 



709-714. June 8, 1895. 



In a recent number of the Revue Scientifique 

 Parinaud gives the results of certain interest- 

 ing experiments upon the relative sensitiveness 

 of the eye to spectral colors seen under different 

 conditions of retinal adaptation. Two degrees 

 of adaptation were used, one that of the eye in 

 ordinary vision, the other that of the eye from 

 which light has been completely excluded for 

 20-30 minutes. The following little table gives 



Condition of the 

 Eetina. 



20-30 min. darkness... 

 Ordinary conditions... 



the general results of the experiments, the let- 

 ters standing for the Fraunhofer lines. While 

 the figures are not to be taken in any sense as 

 absolute, there are several interesting relations 

 that appear in them. 



The red end of the spectrum, for example, 

 appears wholly unaffected by adaptation, thougli 

 the place of greatest brightness shifts decidedly 

 toward the violet. It was observed further 

 that, with the adapted eye and the low intensi- 

 ties of light used with it, colors from the yellow 

 onward to the violet (t. e., the colors which are 

 influenced by adaptation) appeared colorless ; 

 in other words, adaptation of the eye decreases 

 the saturation of the colors seen until they at 

 last appear entirely white. The red end is 

 seen as red if seen at all. A third observa- 



