August 31, 1906.] 



SCIENCE. 



281 



3, notes et revxie, pp. cxxiii-cxxxii. 

 MOEGAN, T. H. 



1905. The assumed purity of the germ-cells in 

 Mendelian results. Science, n. s., vol. 22, pp. 



877-879. 



TSCHEEMAK, E. 



1906. Ueber Bildung neuer Formen durch 

 Kreuzung. Resultats sci. du Congres internat. 

 de Botanique, Wien, 1905, pp. 323-330. 

 Fischer, Jena. 



Wilson, E. B. 



1906. Mendelian inheritance and the purity of 

 the gametes. Science, n. s., vol. 23, pp. 112- 

 113. 



W. E. Castle. 

 Zoological Labokatoey, Hakvaed 

 University, July 23, 1906. 



preliminary description of two new species 

 OF the genus dioeratherium marsh, from 



THE agate spring FOSSIL QUARRY. 



Among the commoner forms obtained by 

 field parties of the Carnegie Musenin in this 

 rich deposit of bones, which has previously 

 been described,^ are two new species, provi- 

 sionally referred to the genus Diceraiherium. 



The fact that Diceratherium is found in 

 this horizon, which has been regarded as late 

 Tertiary (by Marsh as Pliocene) is highly 

 interesting, and it was thought by the present 

 writer (I. c, p. 491) that it might possibly 

 belong in the lower Miocene. The study of 

 the new material reveals the fact that the 

 animals here represented are apparently some- 

 what more modified than the Diceratheria 

 from the John Day beds. 



The geological horizon in which this quarry 

 is situated is at the top of the Harrison beds 

 (Dsemonelix beds of Barbour, or the upper 

 Arikaree of Darton). This entire section, 

 the Gering, the Monroe Creek, the Harrison 

 and the Nebraska beds, which overlie the Oli- 

 gocene, should, I think, be regarded as lower 

 Miocene, though the Nebraska beds may pos- 

 sibly represent the middle Miocene. 



DiceroAlieriwm niohrarensis, n. sp. 



The type, No. 1,271, of this species is a 

 well-preserved skull, with the nasals disarticu- 

 lated at the fronto-nasal suture. The nasals 



'^ AnnalR of the Carnegie Musetom, Vol. III., 

 pp. 487-494, 1906. 



were found in the talus below the point where 

 the skull was obtained, and presumably be- 

 longed to it. The premaxillaries are wanting, 

 as is also the posterior portion of the left 

 zygomatic arch. Except P^ and the incisors 

 the dentition on both sides is beautifully pre- 

 served. The principal characters of the type 

 are as follows : Skull mesaticephalic. 



1^ 

 ^2?' 







3?' 



M, 



The brain-case is large, the occiput high, and 

 there is a well-formed sagittal crest with a 

 narrow and rather shallow groove in the 

 median line. The frontals are quite broad 

 and convex laterally. When the nasals, which 

 undoubtedly belong to the same specimen, are 

 placed in position, they, with the frontals and 

 parietals, unite in displaying an antero-pos- 

 terior saddle-shaped concavity on the top of 

 the skulk Near the anterior extremity the 

 nasals are provided with a pair of well de- 

 veloped horn-cores, about 24 mm. long, rugose 

 and subtriangular in section. Anterior to the 

 base of the horn-cores the nasals are rapidly 

 abbreviated, terminating in a blunt point pro- 

 jecting forward and downward. The narial 

 openings, the foramen magnpm, and the orbits 

 are large. The infraorbital foramen is situ- 

 ated above the anterior part of P^ The 

 zygomatic arch is rather slender. There is 

 no large tubercle on the supra-occipital as in 

 Diceraiherium armaium, but there is a promi- 

 nent median ridge, which continues from near 

 the superior margin of the foramen magnum 

 to the top of the inion. The foramen magnum 

 is subtriangular in outline. The occipital 

 condyles are large and well separated by a 

 broad median notch inferiorly. The par- 

 occipital and postglenoid processes are very 

 prominent, and their bases almost touch one 

 another. The posterior nares extend forward 

 to the anterior part of M". As has been stated, 

 the first premolar is unfortunately not present 

 in the type, but another individual of the same 

 species (No. 1,273) shows this tooth much 

 more reduced than in Diceratherium armatum. 

 All the teeth have internal and external 

 cingula, and are otherwise quite similar to 

 those found in the species from the John Day. 



