70 KANSAS ACADEMY OF SCIENCE. 



sions, as in the case of the typical species. The leaves also differ (^uite perceptibly, 

 being much larger for the same age in the variation, and having larger petioles, 

 both for the leaf proper and for the leaflets. The margins are more strongly ser- 

 rate, tending to double serrate. The internodes of the stem are much longer in the 

 Tariety, causing the leaves to be fewer and more scattered. The nodes are more 

 swollen, as are the leaf petioles at the base, making a much larger leaf scar, but the 

 axillary buds are smaller. The stem of the type species is quite rough, furrowed, 

 and warty, especially as it grows older, while the variety is much smoother. The 

 fruit of the variety is more abundant, berries larger, and in more open corymbs. 



lu short, the whole aspect of the variety is more grape-like, and for this reason 

 we suggest the name A. quinquefolia, var. vitacea. 



NOTES ON "MOUNTAIN LEATHER," FEOM RED ROCK CANON. 



COLORADO. 



BY E. B. KNEBB. 



The red sandstone of the Red Rock Canon, Colorado, along the Colorado Mid- 

 land railroad, is extensively quarried for building purposes. In the seams and 

 joints of this rock may be found a tenacious asbestos or paper-like mineral, known 

 as "mountain leather." When the seam is large, allowing of a thicker deposit, the 

 mineral is rather spongy, and is then known as "mountain cork." An analysis of 

 the mineral gave the composition as follows: 



SiOz 59.02 



AI2O3 8. .51 



MgO 9.57 



K.,0 81 



Na^O 4.28 



H.O 18.21 



100 . 40 • 



RECENT ADVANCES IN THE STUDY OF THE NERVOUS SYSTEM. 



BY C. JUDSON HEBBICK, OTTAWA. 



The past decade has been a period of unparalleled activity in the study of the 

 nervous system, both human and comparative. Investigation has appreciated more 

 and more the value of the latter method. The points mentioned in this brief review 

 are almost all the direct outgrowths of improved histological and embryological 

 methods. 



One of the most valuable results of these studies has been the establishment of 

 safe homologies through the entire series of vertebrates, from the fish to man. The 

 commissures have naturally received especial attention. The cailosum, formerly 

 supposed to belong exclusively to the higher mammals, has, in recent years, been 

 found by various observer^ in the kangaroo, n few birds, serpents, and batrachians. 

 About two years ago, it was found by my brother in the alligator,* and by him last 

 year in the opossum, strongly developed.! Last winter, in working up material col- 



• Notes on tho Brain of the Alllf,'i>tor, by C. L. Herrick, .Toiirnal of Cincinnati Society of Natural 

 History, 1890. 



tJouriial of Coiuparatlve NouroloKy, February, 1802. 



