XVI THE INSECTIVOROUS OTTER 513 
L. mergulus, is about the size of Mus rattus; it has webbed 
toes and a powerful laterally-compressed tail. Clavicles are 
present, which is not the case with Potamogale. 
Oryzoryctes is a Mole-like Centetid. It has fossorial fore- 
limbs, but a fairly long tail. This genus is furry like the last 
two. It is said to burrow in the rice-fields and to do much 
harm. The teeth are forty in number, three incisors and three 
molars in each half of each jaw. . 
Fam. 4. Potamogalidae.—This family contains two genera, 
Potamogale and Geogale. 
Potamogale velox is a West African animal, which though an 
Insectivore has the habits of an Otter. It is “somewhat larger 
than a stoat.” The upper surface of the body is dark brown, 
the belly brownish yellow. It has a flat head and a long tail 
like the Stoat, but the tail is laterally compressed and very 
thick. The eyes are very small; the nostril has valves. The 
toes are not webbed ; but the second and third toes are united for 
the whole length of their first phalanges. Along the outer side 
of the foot is a thin extension of the integument. In swimming 
the feet are drawn up along the body, hence webbing would be 
of no use; but the thin flattening prevents the edge of the foot 
from acting as a hindrance to the motion of the animal. 
M. du Chaillu describes it as catching fish, which it pursues 
with extreme rapidity in the clear mountain streams it 
frequents; but Dr. Dobson, remarking that no stomachs have 
been examined, thinks that water insects are more probably its 
prey. It is not known whether the animal possesses a caecum. 
The tooth formula’ is 13 C1 Pm3 M3. The animal is excep- 
tional among the Insectivora in having no clavicles.” There are 
sixteen ribs; there is no zygomatic arch, and the pterygoids 
converge posteriorly. 
Geogale, with one species, G. auvrita, is a small representative of 
this family from Madagascar. It has only thirty-four teeth. When 
better known it may be necessary, thinks Mr. Lydekker, to make 
this animal the type of a separate family. The tibia and fibula 
are distinct, hot confluent with one another as in Potamogale. 
Fam. 5. Solenodontidae.—This family contains but a single 
genus. 
' Allman states the canines to be absent. I follow Flower and Lydekker. 
2 See Allman in Zrans. Zool. Soc. vi. 1869, p. 1. 
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