19 



a. Costal grooves 12. 



b. A single indistinct plantar tubercle or none. Black ou 



sides, with a yellow stripe along the back. Head 



broad. Idaho. epixanthwn. 



Leaden brown, with a grayish-brown dorsal stripe. 



Wyoming to Pacific coast. macrodactylum. 



Lead color to black, sometimes with whitish specks 



along the sides. jeffersonianum, p. 22. 



bb. Two distinct plantar tubercles. 



Lower jaw projecting beyond the upper. 



xiphias. Appendix. 

 Lower jaw not projecting perceptibly beyond the 

 upper. Sides with vertical yellow spots. N. Mex- 

 ico, trisniptum. 

 Lower jaw not projecting. Spotted irregularly with 

 yellow. tigrinum, p. 23. 

 aa. Costal grooves 11. 



c. Two distinct plantar tubercles. 



Dark brown above, brownish yellow below. Tail equal 



to rest of body. copeianum, p 26. 



Dark above, with large, irregular yellow spots. Yellow 



below. bicolor. 



cc. No plantar tubercle, or one indistinct. 



Lead color. Tail equal to distance from vent to gular 

 fold. Size small. Pennsylvania to Georgia. 



eompersum. 



Dark above, with a row of yellow spots of size of eye on 



each side of back. pundatum, p. 27. 



Black above, with cross bands of gray. opacum, p. 29. 



aaa. Costal grooves 10. 



Brown, with sprinklings of gray. talpoideum. Appendix. 



Ambystoma mierostomum, (Cope )* 



Small-Mouthed Salamander. 



Figure 1, PL 1. 



Amblystoma mierostomum, Cope, 1867, 1, 206 ; Boulenger, 1882, 28, 50 ; 

 {jhondrotus mierostomus. Cope, 1887, 22, 88; 1889, 51, 101, with figures. 



Body longest and slenderest of all the species of Ambystoma, the dis- 

 tance from the snout to the axilla being contained twice in the distance 

 from the axilla to the groin. Head small and short ; contained in length 



*Although Prof. Cope has assigned this species to his recently proposed genus Chon- 

 drohm, I retain it in Ambystoma ; since a careful examination of the tongue structures 

 has shown that there is no essential difference between these and those of other species 

 of Anihystoma. The otoglossal is identical with that of A. opacum. 



