OCR Text |
Show 124 is smaller than in the three teeth preceding. First lower premolar well developed w i th one root. Enamel of all the teeth, especially of the canines, rugose. This species is allied to those of the genus Pterodon. Measurements. Length of four posterior superior molars 055 Length of first true molar 016 Width of first true molar 015 Length of second true molar 016 Width of third ( transverse) molar , Length of five anterior inferior molars 054 This species is intermediate in size between the O. forcipata and 0. morsitans. The Senultimate inferior molar differs from that of both these species in the much weaker evelopment of the internal lateral tubercle and more obtuse anterior tubercle; in 0. forcipata the blade is continued on the front of this tubercle. Two specimens embracing five series of teeth have been examined by the writer; the measurements given are those of the smaller. OXYJENA MORSITANS, sp. wot?. The geuus of flesh- eat ing mammals, described in 1872 under the name of Stypolophvs, presents a type of dentition which is further illustrated by the present addition of new species much larger than any hitherto known to possess it. Those described are in the order of size: 8. inseetirorus, 8. pungens, and S. brevicalcaratu*, Cope. The present new species is twice the bulk of the last. It is represented by broken mandibles with molars and canines of two specimens, and part of the maxillary dentition of a third. The molar, which is typical of the genus, in its sub triangular basis supporting three elevated cusps, and a short heel, is evidently functionally the sectorial, whatever its hoinological relations may be. In the preseut instance, the inner posterior cusp is much reduced, while there is a small additional cusp jon the front of the anterior near its basis. The trihedral outer posterior forms a cutting edge with the large outer anterior, which is produced forward. A posterior molar exhibits a corresponding tricuspidate portion, and a more elongate heel, with acute circumference. In a premolar, the posterior heel becomes trenchant and median. The canine is very stout and compressed at basis. The enamel in all the teeth is more or less rugose. Measurements. M. Length of base of crown of sectorial tooth .014 Width of base of crown of sectorial tooth 009 Elevation of principal cusps 015 Elevation of inner posterior ensps 007 Length of basis of posterior molar 012 Width of basis of posterior molar 007 Length of heel of posterior molar 005 Elevation of principal cusps 011 Elevation of anterior cusps 006 Long diameter of canine at base 018 The maxillary series belongs to a still larger animal. The sectorial presents the same form as that of the mandibular series, and is more robust in form than in existing Carnirora. The section of the middle crests is very convex on the inner side, so that the shear is oblique. The heel is small and low. The premolar preceding has a large, broad heel. In another premolar, the heel supports a median crest, while the anterior part of the crown is a slightly- compressed cone, with a small tubercle at the anterior base. Other specimens indicate that this species lacks the inferior incisor teeth. OXY^ ENA FORCIPATA, sp. nov. Char, specif.-- Mandibular rami robust and deep, with the symphysis short, and the chin contracted. The canine tooth forms a vertical oval in section. The first one-rooted premolar is a stout tooth ; there is no anterior basal tubercle on the second and third premolars, but a distinct one on the first true molar. There is a small tubercle at the base of the anterior lobe of the last or second sectorial molar. This tooth is larger than the penultimate. The enamel of all the teeth is quite rugose, although they are well worn by use. Corresponding characters are exhibited by four specimens of this species, one of. which includes portions of the upper jaw. All the bones are particularly massive, and there is a high parietal crest, a fair indication of the size of the temporal muBoles. Additional specimens of the Oxycena morsitans, Cope, show that it differs in the reduced size of the sectorial molars, and the very small first premolar, whicli is quite rudimental. |