XVI THE INSECTIVOROUS OTTER 513 



L. mergulus, is about the size of J\[iis rattus ; it has webbed 

 toes and a powerful laterally - compressed tail. Clavicles are 

 present, which is not the case with Potamogalc. 



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 

 liarm. 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, 

 Potamogcde 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 Ms I f C -^ Pm f M f . 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. aurita, 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, not 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 Trans. Zool. Soc. vi. 1869, p. 1. 

 VOL. X 2 L 



