38 REVISION OF AMERICAN MOLES— TRVE. 



depression or an irregularity of the structure of tbe bone wIkcIi ^youId 

 lead one to sus])ect that a careful histological study of the region might 

 bring a rudiment of the tooth to light in numy instances. 



The most common cases of suppression of teeth are those in which 

 one or both of the filiform second and third upper incisors are absent. 

 In many cases the absence of these teeth is probably due to ordinary 

 wear, but in other cases they appear to have been absent from the start. 

 Some eight or nine such cases have come under my observation. A 

 very singular abnormality in a skull from Mississippi (skin No. 7268 i!>r. 

 M.) is the absence of the first lower incisor on both sides. In five cases I 

 have found the first upper premolar lacking either on one side or on 

 both sides. 



jSTone of these abnormalities can be correlated with geographical dis- 

 tribution, but occur si)oradically in difterent parts of the country. In 

 no case where I have been able to examine two or more skulls from one 

 locality have I found the same abnormality repeated.' 



There is a considera.ble amount of abnormality in coloration in the 

 genus, but it may be said that it always takes the form of complete 

 or partial albinism unless the presence of a rusty suffusion may be 



'dental variations in specimens of SCAEOPS AQlTATICrs KXAMIXEI). 



A. N. S. r. 3532. Woodville, Alabama. 



Lacks first n])per i)remolar on each side and also second upper incisor on each 

 side. (Does not ditler otherwise, so far as I can tee. Head skin has large 

 white blotch nn<ler right arm. ) 

 D. A. .".138(5. 



Lacks I ' on both sides. Proliably fallen out, as teeth are all much worn. 

 N. M. 4853. Carlisle, Pennsylvania. 



Lacks I ' on both sides and PJ\l ' on left side. There are depressions, however, 

 and the teeth have rerji probably dropjied out. All the teeth much worn. 

 N. M. 1142. Washington, INIississippi. 



I ^ very large. (Skull looks narrow.) 

 N. M. 955. Carlisle, Pennsylvania. 



Has an I 3 on each side. Small, but very <listinct. 

 N. M. 3,5292. North Carolina. 



Lacks PM ^ right side. Evidently deciduous. 

 N. M. 3922. Georgia? 



Kight I ' and I ^ and left I - wanting. Those of the right side seem to be merely 

 worn down to the gnm. The lower jaw has a trace of an I i? on each side in 

 the gum. 

 N. M. 1638. St. Louis, Missouri. 



Left I - and I ^ and right I -^ wanting. All teeth much worn. 

 A. M. 4489. Rock])ort, Texas. 



Only a trace of I ' and I ■' left side ;ind I ' right side. 

 A. M. 4485. Rockport, Texas. 



Only a trace of I ^ and I ^ both sides. 

 A. M. 895. Raleigh, North Carolina. 



1 2. and I ^ left side and I -- right, wanting. Evidently deciduous. 

 A. M. 1002. Raleigh, North Carolina. 



Has a small I 7 on left side. 



