I 
AND AFFINITIES OF POTAMOGALE, 
second incisor is separated from the first by a narrow space which receives the second 
incisor of the lower jaw when the mouth is closed ; it is triangular, compressed, with a 
sharp anterior and a sharp posterior edge—the anterior edge being convex, and the 
posterior slightly concave. The third incisor is of the same form as the second, but a 
little smaller. The incisors are each implanted by a single fang. 
Since in the view here adopted the canine is supposed to be absent, the first pre- 
molar follows immediately on the third incisor, with an interval so slight as to have no 
claim to be regarded as a distinct diastema; it is inserted by two fangs; its crown is 
slightly larger than that of the third incisor, but otherwise it resembles it. The second 
premolar is also implanted by two fangs, and is otherwise similar to the first. The third 
has the form of a triangular pyramid, with a small cusp developed from the posterior 
internal basal angle, and another from the posterior external; it is implanted by three 
fangs. 
The first, second, and third true molars are similar to one another: they are trian- 
gular in horizontal section, with» the apex of the triangle situated internally; the 
greatest antero-posterior diameter of the crown is to its transverse diameter as 2: 3; 
the internal. angle of the crown presents a single cusp; the centre, two; and the 
external side projects downwards as a tuberculate ridge; they are each implanted by 
three fangs. 
In the lower jaw (Pl. II. & fig. 8, p. 11) the incisors present, as in the upper, the 
usual single-fanged insertion.- The first is very small, chisel-shaped, and with its crown 
conyerging to that of its fellow. The second incisor is high, conical, curved, with the 
concavity of the curve looking backwards, and presenting from its base to its apex two 
surfaces separated by a sharp ridge ; it is sharp-pointed, and resembles a canine; it is the 
most projecting tooth in the jaw. The third incisor is small, irregularly conical, convex 
anteriorly, concave posteriorly ; it is the smallest of the teeth, except the first incisor. 
The first premolar is triangular, compressed, with a sharp convex anterior edge and a 
sharp concave posterior edge ; it has but a single fang. ‘The second premolar is trian- 
gular, compressed, with sharp anterior and posterior edges; it is implanted by two 
fangs; its crown is a little lower than that of the first, but it otherwise resembles it. 
The third premolar is a little larger than the first, triangular, compressed, with sharp 
anterior and posterior edges; the anterior and posterior basal angles have each a small 
tubercle; it is implanted by two fangs. 
The first, second, and third true molars are prismatic, and equal in height to the 
second premolar; the crown is furnished with three cusps in front and a single one on 
a lower level behind. They are each implanted by two fangs. 
A very striking aspect is given to the dental series by the form of the crowns of the 
second, third, fourth, and fifth teeth of the upper jaw, which are all triangular, much 
compressed, with sharp anterior and posterior edges, thus vividly reminding us of the 
teeth of certain sharks. In this respect they resemble the premolar teeth of the viver- 
