1894.] 



NATURAL SCIENCES OF PHILADELPHIA. 



239 



fleinarkation between colors of upper and lower parts everywhere 

 sharp and distinct. 



Cranial and dental characters. — Most of the cranial and dental 

 characters have been already given under the head of the genus 

 and need not l)e here repeated. The rostrum is short and the ascend- 

 ing branches of the premaxilhe hardly reach as far back as the nasals. 

 Molars large and broad ; m ^ more than half as broad as long and 



Fig. 4. A'eiw/iij's nelsoni Type. Upper and lower 

 molar crowns, (x 7.) 



curving outward anteriorly ; m j with anterior half bent strongly 

 outward, the anterior loop looking outward instead of forward; m y, 

 S-shaped, with a small and nearly closed triangle on outer side of 

 convexity, thus having an anterior loop projecting inward, a poste- 

 rior loop projecting outward, and a re-entrant angle or loop on each 

 side, the outer of which is the shallower and more posterior in posi- 

 tion ; both of the re-entrant angles are directed obliquely forward as 

 well as toward the opposite side of the tooth (for further details see 

 fig. 4). 



Measurement.-^ of type (taken in flesh). — Total length, 300 mm; 

 tail vertebrte, 143; hind foot, 30; ear 22 (in dry skin). 



Cranial measurements of type. — Total length, 40.5; basal length, 

 35; basilar length of Hensel, 33; zygomatic breadth, 21; upper molar 

 series on crowns, 8. 



Genus NEOTOMA Say and Ord. 



Neotoma Say and Ord, Journ. Acad. Nat. Sci. Phila., IV, pt. 2, 1825. 345, 346, 

 pl.s. XXI and XXII Type Mns ftoridana Ord, from eastern Florida. 



Generic characters.^^ — Crown of in 3 composed of two transverse 



" Tile character.s here given are selected with reference to antithesis with 

 P/]'ssop/ioriis, Hodoniys, and Xenoniys. 



