Mr. R. F. Tomes on species of Bats inhahiting New Zealand. 391 



in two straight lines which are nearly parallel, the incisors only de- 

 viating from these lines, being placed across the front of the space 

 enclosed by them. This enclosed space — constituting the anterior 

 part of the palate — is nearly a parallelogram, being but slightly nar- 

 rower in front than posteriorly. Its length to its breadth is as one 

 and a quarter to one. 



The range of the teeth in the lower jaw must, of course, bear exact 

 relation to that of the upper *, varying only in the number of the 

 teeth and their individual form. 



The number of the teeth is as follows : — 



In. ^-^ ; Can. i^ ; Premol. --fJ ; Mol. |55 = 1|. 



The upper incisors are arranged in pairs, of which the inner one 

 of each pair is much larger than the outer one. They are all some- 

 what elongated, conical, and pointed, and when viewed in front are 

 seen to have their points directed inwards, but when seen laterally 

 have nearly a vertical direction, similar in this respect to the canines. 

 A considerable interval separates them on each side from the latter 

 teeth, and this, with their regular conical outline and nearly vertical 

 position, constitute their chief peculiarities. In the centre, between 

 the inner ones, is a considerable opening, caused by the non-deve- 

 lopment of the anterior margins of the intermaxillary bones, and the 

 notch in the front of the palate, just as in the Noctule Bat and most 

 other true Vespertilionidce. The other teeth in the upper jaw pre- 

 sent no deviations from what is usual in the genus. 



In the lower jaw the incisors are of the form ordinarily observed 

 in this genus ; they are symmetrically arranged and trilobed. The 

 canines present no marked peculiarities of form. The premolars are 

 small, pointed, and have their basal cusps less developed than those 

 of the corresponding teeth in the Noctule Bat. The first of these 

 teeth is much the smaller of the two. The molars differ in no re- 

 spect from those of the above-mentioned species, excepting that their 

 cusps are perhaps somewhat longer and more pointed. 



In the following Table of dimensions, the first column represents 

 the measurements of the specimen in spirit in the Museum of the 



* It will not be out of place here to remark, that this expression applies ex- 

 clusively to the normal state of dentition of animals in a state of nature. The 

 reverse of this may occasionally be seen in accidental varieties or malformations, 

 and frequently in domesticated animals, where a great change in the form of the 

 jaws and teeth has often resulted from long-continued selection of individuals 

 from which to produce a breed for some special purpose, which selection may 

 have been further assisted by a constant training to the purpose for which the 

 breed was designed. This must certainly be the case with some of the varieties 

 of dogs. In the bull-dog, for instance, we find a most remarkable development 

 of lower jaw, attended with an equally distorted arrangement of the teeth. It 

 is scarcely necessary to allude to the singular appearance often observable in the 

 front teeth of the human species, under- or over-lapping each other, as the case 

 may be, and displaying every degree of intermediate arrangement. But these 

 deviations from the normal state of dentition in no way affect the statement above 

 made respecting the relation of the inferior to the superior maxilla, and their im- 

 planted teeth. 



