1898] NOTES AND COMMENTS 159 



by the expeditions of the American Museum under Dr J. L. Wort- 

 liian, during 189 2 and 1894, from the Oligocene White River Beds 

 of Nebraska and Dakota. These present a very large and perfect 

 series of skulls, many of them associated with fairly complete 

 skeletons. 



Future parts of the monograph will deal with the Aceratheres 

 of the American Miocene ; the Aceratheres and Rhinoceroses of 

 Europe in comparison with those of America, skeletal characters of 

 American Aceratheres, and final classification of the Rhinocerotidae.; 

 the Amynodontidae ; and finally the Hyracodontidae. Professor 

 Osborn states that it is his one single purpose " to establish a sound 

 philosophical basis for the morphology of the Rhinoceroses, derived 

 from their primitive, parallel, and divergent characters, and leading 

 toward the discovery of their origin, phylogeny, and distribution." 

 If the remaining parts of his Memoir are like that now before us, he 

 is fairly assured of success. 



On Cyclamen 



The well-known genus Cyclamen is the subject of an exhaustive 

 memoir by Dr Friedrich Hildebrand of Freiburg, which has been 

 recently published by Fischer of Jena. The thirteen species are 

 almost confined to the Mediterranean region, spreading northwards 

 only as far as southern Germany, and eastwards to the Caucasus. 

 Cyclamen is a good example of adaptation to the climatic conditions 

 prevailing in the district in question. A season of luxuriant growth 

 alternates with a season of rest, but the determining factor is not, 

 as in higher latitudes, the appearance or disappearance of continued 

 frosts, but variation in the amount of moisture. Hence the most 

 striking characteristic of this plant is the great tuber, which, like the 

 bulb of the lily or the corm of the crocus, enables it to remain alive 

 during the dry season. It is interesting to note that an important 

 systematic character resides in this highly adapted structure, since in 

 some species the tuber protects its contents by a corky layer, in others 

 by a felt-like covering of hair. Its early development again is of 

 great interest. The nourishment stored in a seed is generally used 

 up on germination in the production of one or more green leaves, the 

 assimilating organs, by aid of which the seedling becomes an inde- 

 pendent organism. Cyclamen, however, has become so impressed 

 with the importance of forming a tuber, that it starts even before 

 the unfolding of the first leaf, which means that some of the reserve 

 nourishment Btored in the seed is not used to make leaf-tissue, but 

 is passed down the leaf-stalk to form a new reservoir in the short 

 stem just above the young root. 



There has been much argument as to the cotyledons of Cyclamen. 

 As a member of the primrose family, and, therefore, a dicotyledon, it 



