715 
was such an exception that not one male existed among forty 
females. 
The Mastodon of Philadelphia, Mr. Koch says, is ‘a male, ac- 
‘cording to the construction and size of the pelvis and ‘the magni- 
tude of the tusks in the upper jaw, yet there are no traces of tusks 
in thelower jaw; and the specimen at Baltimore, which is considered 
ito be indisputably amale, is also destitute of inferior tusks. The au- 
thor likewise states that he has uniformly found the jaws of young 
Mastodons to be very rare ; that those which he has seen have no 
indications of tusks ; and that‘he has in his possession the lewer jaw 
of a':voung Mastodon, mentioned by Dr. Hay, which ‘has ‘no tusks. 
Hence he infers that there are young Mastodons, as well as Tetra- 
cauledons. 
Mr. Koch then proceeds to draw attention to ‘some important 
points’ which he believes have not been noticed. 
Admitting, for the sake of argument, that the male Mastodon 
was the possessor of the small tusks only eight or twelve inches 
long in the lower jaw, he says it would have been utterly impossi- 
ble for that animal, with his enormous upper tusks and short neck, 
to have reached the ground with them ; yet these small lower tusks, 
he states, show that they were much used in rooting and grubbing, 
and therefore must have belonged to an animal which had equally 
‘short upper tusks. To substantiate this inference he calls attention 
to three species of Tetracaulodon, the first discovered by Dr. God- 
man, the two others by himself. 
1. Tetracaulodon Godmanii.—This species having been described 
in detail by Dr. Godman, Mr. Koch only points out the great dif- 
ference of the maxillary and nasal bones, as well as the additional 
foramina near the malar bone, which are wanting in the Elephant 
and Mastodon. He says that in his collection there is a fragment 
of a lower jaw of this species with a tusk which shows very distinctly 
the difference of the lower tusks in the T. Godmanzi from those of 
the T. Kochi, the character consisting in the root of the tusk being 
pointed ; and he states that he has not been able to discover the 
place occupied by the dental nerve. 
2. Tetracaulodon Kochiu,—Of this “‘ species” the author pos- 
sesses three lower jaws of adults, and one of an extremely young 
animal ; also two upper tusks belonging to two different individuals, 
and two which belonged to one Tetracaulodon. Mr. Koch states 
that he found the roof of a mouth of this species perfect, with its six 
molar teeth and the tusks in their “ maxillary bones” resting on the 
lower jaw which retained a tusk in the alveolus, but that the veins 
of iron intersecting the deposit prevented him from extracting this 
valuable specimen entire, but that he secured the upper tusks and 
grinders, and the lower jaw with the tusk in its alveolus. It does 
not require a close examination, the author says, to perceive that 
the animal to which these remains belonged was neither male, fe- 
male, nor young Mastodon, or Missourium, the whole inner and 
outer conformation of the upper tusks showing that they were cal- 
culated to be used in harmony with the lower tusk in grubbing 
