38 
- By Arthur Hollick (Department of Geology, Columbia 
College). 
175. New Species of CRETACEOUS (Dakota Group) LEAVES, 
from the West. Two of the species (Lirzophyllum populoides 
Lesq. and Lzrzodendron alatum Newb.) have wing-like appen- 
dages to the petioles, first described in Bull. Torr. Bot. Club, 
Nov., 1894, which apparently represent the beginnings of what 
we now know as stipular appendages to the leaves. 
176. New Species of CRETACEOUS (Laramie Group) LEAVES, 
mostly from Colorado, now being studied for description in 
connection with a forthcoming Bulletin of the U. S. Geol. 
Survey. 
177. Specimens of CRETACEOUS LEAVES AND MOLLUSCS from 
Martha’s Vineyard, part collected personally, the remainder, 
recently sent for identification from the U. S. Geol. Survey. 
These latter represent the best portion of the material collected 
by Mr. David White, described in Am. Fourn. Sct., xxxix. 
(1890), 93-101, which first demonstrated conclusively the ex- 
istence of cretaceous strata at Gay Head. 
By Department of Vertebrate Paleontology, American Mu- 
seum of Natural History. Exhibit arranged by Henry F. Osborn, 
Curator, and J. L. Wortman, in charge of field expeditions. 
This department was established in 1891, and explorations 
have since been actively carried on inthe Rocky Mountain region, 
principally in New Mexico, Utah, Wyoming, and Dakota, result- 
ing in the discovery of a large number of rare types. 
178. EVOLUTION OF THE HORNS OF THE TITANOTHERES. This 
represents four stages in the evolution of the horns in animals 
of a remarkable group which lived in North America during 
the Eocene and lower Miocene periods. Specimen @ shows 
the skull of Palwosyops, a middle Eocene ancestral form with- 
out horns; 4, skull of Telmatotherium validum, shows the very 
first suggestions of the appearance of a horn at the point indi- 
cated by the white arrow; c,skull of Telmatotherium cornutum 
(upper Eocene), shows the incipient horn clearly marked, also 
indicated by white arrow; d, skull of 77tanotherium coloradense 
(lower Miocene), shows short but well developed horns; and g, 
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