E. L. Troxell — Polceolagus, an Extinct Hare. 347 



the first milk tooth partakes of the character of the third 

 lower premolar in Lepus, in having three lobes, but the 

 marks of these lobes do not go beyond half the length of 

 the short-crowned teeth. The second deciduous tooth of 

 this specimen, also short-crowned, shows the distinct, 



Fig. 18. 



Fig. 17. — Falceolagus haydeni agapetillus. Cat. No. 12076, Y. P. M. 

 Upper and side view of mandible, with deciduous premolars and first true 

 molar. X 2. 



Fig. 18. — Falceolagus haydeni. Cat. No. 12071, Y. P. M. Upper and 

 out^r side views of mandible, with two deciduous and three permanent 

 teeth. X 2. 



small, posterior lobe which is prophetic of the true molars. 

 The interesting first molar will be discussed below. 



Specimen No. 12071 {fig. 18) shows the first milk tooth 

 with the most of the inner folds eliminated by wear. All 

 track is lost of the posterior or third lobe in the second 



Fig. 19. 



Fig. 20. 



Fig. 19. — Falceolagus Jiaydeni agapetillus. Cat. No. 12077, Y. P. M. 

 Crown view of ramus of mandible. A very small subspecies. X ^' 



Fig. 20. — Falceolagus haydeni. Cat. No. 12075, Y. P. M. Top and side 

 \dews of lower jaw, showing deciduous premolars, Dp^.^, and anterior half of 

 first true molar, Mj. X 2- 



milk tooth. Both Mj.g have the small third lobes; this 

 cusp in the unworn M2 is separated from the larger lobe, 

 but Ml illustrates well how it becomes attached after only 

 a little wear. 



Another specimen (^g. 19) consists of the right ramus 

 of a very small individual, probably the typical P. agape- 



