PROCEEDINGS OF THE NATIONAL MUSEUM. 99 



The differences in dentition are much more than mere absence of one 

 tooth above in Neurotrielms and one below in Urotrichxs. The Japa- 

 nese mole has the first upper incisor long, slender, and curved, with an 

 external accessory cusi), while in Ncilrotrichus this tooth is broad and 

 flat. The second tooth in Urotrichus is like the first, but only about 

 half the size, while the third and fourth are minute and simple. In 

 Ne Urotrichus the second and third teeth are about equal in size (much 

 smaller than the first) and compressed, while the fourth is much larger, 

 thick and conical. Leaving out of consideration the fifth tooth in Uro- 

 trichus, the sixth is single-rooted, while in N'eiirotrichus the correspond- 

 ing tooth (fifth) is double-rooted. 



In the mandibular teeth the differences are fully as striking. The first 

 four teeth in Neiirotrichus have rounded oblique crowns, and are gradu- 

 ated in size from in front backward. In Urotrichus the first and second 

 teeth are somewhat like the upper ones, long and crooked, the second 

 much smaller than the first, with a linear and very oblique crown; tlien 

 follows a tooth of medium size with oblique, somewhat spatulate crown, 

 and another very small one. 



The milk dentition of NeUrotrichus in some particulars resembles that 

 of the Japanese mole more than the permanent dentition, but I have not 

 been able to examine a specimen of the American mole with complete 

 milk dentition. 



The Japanese mole is much larger than NeUrotrichus. 



NEUROTRICHUS GIBBSII (Baird). 

 GIBBS' MOLE, 



Urotrichus gibhsii, Baird, Kept. Pacific R. R. Survey, VIII, 1857, p. 76, jil. 



XXVIII ; Mammals of North America, 1859, p. 76, pi. xxviii. 

 Neiiroirichu,<i fjihhsii, Gunther, Proc. Zool. Soc. London, 1880, p. Ill, pi. xiji. 



Diagnosis. — Tail two-thirds the length of the head and body, scaly 

 and sparsely clothed with long black hairs. Feet scaly and sparsely 

 clothed like the tail. Fore foot two-thirds as long as hind foot,^ and a 

 little more than half as broad as long. Fore claws longer than the toes. 

 Eye minute. Auricular orifice large. 



Color uniform deep dusky brown, with hoary reflections and purple 

 iridescence. 



Upper canine two-rooted. Second and third upper incisors small, 

 subequal. Crowns of lower incisors and canine oblique. Mandibular 

 angle slender and curved. 



Arcrafje dimensioiis of 33 specimens from kSumas, British Gohimhia. — 

 Total length, 113.6 mm.; tail, 37.1 mm.; hind foot, 1G.6 mm. 



Ai^erage (Jimensions of 12 sTiulls from ^iimas, British CoJumhia. — Total 

 length, 22.8 mm.; basilar length (Hensel), 18.3 mm.; mastoid breadth, 



1 Exclusive of the claw in both cases. 



