322 



THE NATURE BOOK 



expected, certain peculiarities of his own. 

 Tliough essentially an aquatic animal, 

 the moditications of his limbs and body 

 to suit an aquatic life are trifling. His 

 feet and tail are perhaps more liea\-ily 



^. ^ .-^f^^^x^^H*-- -■* 



VERTICAL SECTION THROUGH LOWER JA^' 

 OF WATER SHREW MOUSE. 



A, 1st incisor. B, 2nd incisor. C, Premolar. 

 D, E, F, Molars. 



haired than those of an adult Common 

 Shrew Mouse, though not more heavily 

 than those of a young Common Shrew 

 Mouse or of a Pygmy. Apart from 

 this, the Water Shrew Mouse might be 

 regarded, externally, as a large blue-black 

 land Shrew Mouse, whose nose had grown 

 fleshy with age, and who had taken to 

 the water as a convenient way of catching 

 fish. I have kept Water Shrew Mice in 

 captivity for long periods, and have had 

 frequent opportunities of watching them 

 in the water, both at large and in cap- 

 tivity, at very close quarters. Like 

 Water Rats, they hate a long immersion, 

 which has the effect of soddening the hair 

 on their back and head. The grey, silvery 

 apjiearance which the fur of a submerged 

 Water Shrew Mouse presents owing to 

 the entanglement of numerous small air 

 bubbles between the hairs, has been often 

 commented on. but may be observed on 

 any fur-clad animal which dives. The 

 swimming of a Water Shrew Mouse, 

 both on and below the surface, is a quick 

 dog's paddle, all four feet being em])loyed. 

 On the surface the head is slightly raised, 

 and three-quarters of the body are out of 

 water. The tail trails behind, and is 

 apparently quite functionless as regards 

 either swimming or steering. Below the 

 surface the head appears to be stretched 

 forward horizontally. 



When scared, the Water Shrew Mouse 

 enters the water anyhow, and I have 

 known one to break his back by jumping 



on to a stone in a pond which had been 

 drained by pumping operations in the 

 vicinity. In the ordinary way, however, 

 as I have had frequent opportunities of 

 observing, the plunge is a matter of some 

 ceremony. He pauses, with his feet 

 gathered together, and pushes off quietly 

 with his hind legs. He thus keeps his 

 head and back dry. He dives very neatly 

 from the surface, and will do so at the 

 slightest suspicion of danger, though a 



Cl, 1st incisor. I>, 1st incisor. 



minute premolar. 



1. SKULL OF THE COMMON SHREW MOUSE. 



2. LOWER JAW OF THE WATER SHREW MOUSE. 



3. UPPER JAWS OF THE COMMON SHREW MOUSE 

 A remarkable feature of the skull is the absence of a 



complete zygomatic arch. 

 The teeth are remarkable in many respects. In the three 

 British Shrew Mice they are tipped with rich orange. 

 The 1st incisors in both jaws are massive, those of 

 the upper jaw being double-pronged, while those of the 

 lower, before becoming worn are serrated. The 2nd 

 incisor in the lower jaw is a small tooth, and the 1st 

 premolar in the upper jaw is microscopic. 



preliminary scramble o\-er water-weeds 

 is often necessary. 



The natural food of the Water Shrew 

 Mouse consists, I think, mainly of mollusca. 

 He eats these very quickly, and with the 

 air of one who knows them. In addition. 



