. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. MUSEUM OF COMPARATIVE ZOOLOGY. 159 fessor Leidy* in 1873, and agrees closely with the corresponding portions of the smallest skull in the Cambridge collection, both in form and measurement. The skull is entire, and enables us to fully define this species. Dentition : I. L^> C. i, Pm. ^, M. No diastema behind the canine. Second upper incisor sometimes wanting. First upper premolar small. Last upper molar without distinct second cone. Upper premolars with a strong internal cingulum. Anterior nares transv
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. MUSEUM OF COMPARATIVE ZOOLOGY. 159 fessor Leidy* in 1873, and agrees closely with the corresponding portions of the smallest skull in the Cambridge collection, both in form and measurement. The skull is entire, and enables us to fully define this species. Dentition : I. L^> C. i, Pm. ^, M. No diastema behind the canine. Second upper incisor sometimes wanting. First upper premolar small. Last upper molar without distinct second cone. Upper premolars with a strong internal cingulum. Anterior nares transversely broad and shallow vertically. Nasals long and broad. Horns short and stout, obliquely compressed at the base so that their faces point in three directions, erect and slightly recurved when viewed from the side. The greatest diameter at the base is fore and aft. Orbits large, and widely open. Superciliary ridge not prominent. Zygomatic arches broad and powerful, but without flanges. Post-glenoid and post-tym- panic processes separate or not broadly Figure 3. — Anterior portion of the skull of three specie^ of Menodus, showing the rela- tions of the nasals to the horns in side view. 1. M. coloradensis. 2. M. tichoceras. 3. M. dolichoceras. The skull of this individual is considerably smaller than the type of M. ingens, measuring only 27^ inches from the occipital condyles to the tips of the nasals. The superciliary ridges expand into small postorbital processes, which are wanting in the above type. The post-glenoid processes do not touch the post-tympanic. The M. ingens skull has two incisors, while this specimen has but one. It is possible that one or more of the above diff"erences may prove to be of permanent specific value, but in the conformation of the nasals and of the horns, as well as in all other details of proportion, these skulls are apparently closely similar. In comparison with the type of S. trigonoceras, Cope, the horns and nasals have somewh
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Keywords: ., bookauthorha, bookcentury1800, bookdecade1860, booksubjectzoology
