February 2, 1893] 



NATURE 



,21 



I will conclude this portion of my remarks by sug- 

 gesting that some of my audience should repeat these 

 experiments on themselves. If they do so, I should 

 be grateful if they would communicate to me their results. 



PROTOCERAS, THE NEW ARTIODACTYLE. 



LAST year the American Museum of Natural History 

 established a department of mammalian palaeon- 

 tology for the purpose of securing and exhibiting collec- 

 tions from all the tertiary horizons of the west. Dr. 

 J. L. Wortman, well known by his discoveries while 

 associated with Prof. Cope, was put at the head of the 

 field work, and under his direction explorations have 

 already been made in the Laramie or Upper Cretaceous, 

 and in three of the great divisions of the tertiary, namely, 

 the Wasatch, the Puerco, and the Lower Miocene or 

 White River. 



The discovery of the first example of Palaonictis found 

 in America was mentioned in Nature last year. From 

 the Puerco are brought remains of about 400 individuals, 

 adding many new facts to the discoveries of Prof. Cope. 

 From the Laramie are 400 of the small isolated teeth of 

 the kind recently described by Prof. Marsh. These are 

 found by the writer to have a distinctly tertiary rathfer 

 than mesozoic character, and while intermediate between 

 the mesozoic and Puerco species, they decidedly resemble 

 the latter. Meniscoi'sstts, for example, about which there 

 has been so much discussion, proves to be a plagiaulacid, 



j upon the frontals, and the frontals also bear a pair of 

 small conical processes just behind their junction with 

 the nasals. But even more exceptional than these 



, parietal and frontal processes are the great ver- 

 tical plates rising from the maxillaries, slightly 

 recurved, and reaching the full height of the 



j parietal protuberances. Seen from above, these plates 

 are found to be not in contact, but to enclose a 

 long deep cleft, representing the anterior narial opening. 

 This is bridged over posteriorly by the nasals, which, as 

 shown in the second figure, are extremely abbreviated. 



i Correlated with the development of these processes are a 



i number of strong ridges, which form supporting but- 

 tresses for the horns. These extend, as above described, 



I from the sagittal crest outwards, also from the anterior 

 margin of the orbit forwards. This lateral maxillary 

 ridge, as it may be called, terminates in a process just 

 above the infraorbital foramen ; and this process, although 

 small, seems to illustrate the remarkable tendency of this 

 little skull to develop osseous projections at every avail- 



FlG. 



-Side view of skull. 



and also an ancestor of Polymastodon, which is thus 

 shown to be a huge Plagiaulax, in which the fourth cutting 

 premolar is reduced. 



By far the most perfect specimens have, however, been 

 brought from the Lower Miocene ; and here it appears 

 that practically a new horizon has been developed, for 

 the collection is full of fresh forms. Many of these are 

 new species intermediate between the true White River 

 or Titanotherium fauna, and the Middle Miocene, but 

 others are new genera, and represent distinct unrelated 

 forms. 



In this Lower Miocene collection are included portions 

 of six skulls and the fore and hind feet of an Artiodactyle, 

 of about the size of a sheep. The most complete skull is 

 here figured exactly as found, and is seen at once to 

 depart from all known Artiodactyles in many important 

 characters. There are no less than four protuberances 

 upon each side of the skull. Hindmost are two processes 

 upon the parietals, which are placed upon the superciliary 

 ridges as they diverge from the sagittal crest. These 

 processes are close together and oval in section, reminding 

 us of the posterior pair of horns in Uintatheriwn rather 

 than of the conical or rounded horns found in the giraffes 

 and some other Artiodactyles. Their position upon the 

 parietal bones is also peculiar. The superciliary ridges 

 extend outwards into two widely projecting plates of bone, 

 which curve upwards above the orbits ; these plates are 



NO. I 2 14, VOL. 47] 



Fig. 2.— Top view of skull. 



able point. The character of these projections is different 

 from that found elsewhere among the Artiodactyla ; they 

 are not horn-cores, neither are they similar to the processes 

 upon the parietals of the giraffe. The development of 

 these multiple bony protuberances suggests the skulls of 

 Sivatherium, Tetraceros, and other eastern ruminants ; 

 but the proportions of the skull are wholly different. The 

 olfactory chamber, which is usually so expanded in the 

 Artiodactyla, is here extremely reduced ; the nasals 

 barely reach beyond the middle line of the skull. 



Up to this point the study of the skull appeared to 

 present an entirely new form, but later the other skulls 

 were removed from the matrix, and among them one was 

 found with small canine teeth, entirely lacking all 

 the processes upon the frontals, and giving indications 

 that those upon the maxillaries were either absent 

 or comparatively small. The parietals were unfortu 

 nately missing, but the idea at once suggested itself tha 

 this might be a female skull. Two years ago Prof 



