252 VERTEBRATE REMAINS, PORT KENNEDY BONE DEPOSIT. 



The determination of this species as distinct from the common wild-cat, with 

 which I at first identified it, reduces the number of existing species by so much. 

 In its character it approaches the primitive or ancestral cats, by a little. 



PROBOSCIDIA. 



MASTODON Cuv. 

 Mastodon americanus Leidy, Ext. Mamm. Dakota, Nebraska, 1869, p. 392. 



Remains of about eighteen mastodons of this species were taken from the 

 fissure. Only one of these exhibits characters of maturity ; several others have 

 one or two true molars unerupted, while others are still younger, one having three 

 premolars in place. 



Two loAver jaws, which contain the last three molars, show considerable dis- 

 crepancy in dimensions, as follows : — 



Measurements, No. 3. 



mm. 

 122 



-r.. r anteroposterior 



Diameters ol m^ < , 



1 \ transverse ; 



Diameters of 



Diameters of m^ 

 Diameters of m T 



anteroposterior ; 200 



transverse ; 80 



No. 4. 



i anteroposterior ; 103 



[ transverse ; 74 



i anteroposterior; 144 



| transverse ; 71 



The last inferior molar of No. 3 is then one-third the length of No. 4 longer 

 than the latter. I have found a few last inferior molars of this species in the large 

 collection of the Academy which approach No. 4 in their reduced size, but none so 

 small in linear measurement. 



The specimens obtained by Mr. Mercer give a full series of the permanent 

 molar dentition. In specimen No. 1 we have pm. 3-2-1 ; No. 2 displays pm. 2-1, 

 m. 1 ; No. 3, pm. 1, m. 1-2-3. This enables me to make a full description of the 

 entire series, but as this has already been done by Falconer, Leidy and others, I 

 will merely restate it briefly. The crests are : pm. 2-2-3 ; m. 3-3-4 and a talon. 

 The premolars are more wrinkled than the true molars. The crest formula agrees 

 with that which I found in the superior dental series of Tetrabelodon productus in 

 1875. The roots of the premolars are long and acuminate. Of the temporary 

 dentition less complete material exists. A temporary molar has nearly the trans- 

 verse diameter of the pm. 2, but has three cross-crests and a cingular tubercle in 

 front. The posterior cross-crest is narrower than the others. As the tooth has 

 both anterior and posterior surface contacts I suppose it to be the &-%. 



The occurrence of these huge animals in the fissure shows that it must have 

 been open at the summit during the plistocene period. 



