io6 



THE NATURE BOOK 



position with his hind feet hidden beneath 

 him (curiously enough Shrew Mice often 

 die sitting) ; but, though body and feet 

 may on such occasions be stationary, 

 head and snout are qui\-ering with re- 

 doubled energy, and I ha\-e little doubt 

 that the Shrew Mouse depends largely on 

 the crown of bristles which encircles the 

 latter for a clear (possibly a tactile) 

 sense of his surround- 

 ings. The importance 

 of these bristles 

 (vibrisscF) is rendered 

 exident by the pre- 

 sence of well-defined 

 muscles to control 

 them. 



A ]:»eculiar feature 

 ■of the Shrew Mouse's 

 brain points to the 

 probability of his pos- 

 sessing an extremely 

 keen sense of s)}iell. 

 We must therefore 

 regard his snout, 

 taken as a whole, as 

 a highly specialized 

 organ, and if. as 

 seems likely from 

 the size and position 

 of his eyes, his range 

 of vision is limited. 

 it may well happen 

 that he finds com- 

 pensation in his ex- 

 tended and delicate senses of smell and 

 touch. 



So far as hearing is concerned, it is 

 difficult to make any crucial experiments 

 with a creature so nervous, restless and 

 highly strung as the Shrew Mouse. .V 

 sudden clap of the hands will make him 

 "jump out of his skin," but this ma\' 

 well be due to terror at the vibration of 

 his surroundings. I have never succeeded 

 in attracting his attention by a soft squeak 

 such as will cause a house mouse to be 

 " all ears " in a moment, nor does a 

 human imitation of his own note, which 

 closely resembles that of the Sabre-tailed 

 Grasshopper {Thamnotrizon), ajipear to 

 interest him. 



His ear, nevertheless, presents certain 

 peculiar features. The conch is circular 

 and almost hairless, both front and back. 

 The Shrew Mouse has the power of con- 



WATER SHREW MOUSE 

 Preparing to dive. 



tracting and folding it in such a way 

 that it may be completely concealed 

 under the surrounding fur. Within the 

 conch are two lobes, or valves, the upper 

 of which is hca\'ily haired on its borders 

 and partly detached from the conch itself, 

 while the lower (a smaller one) seems to 

 be formed by an infolding of the conch, 

 and serves to close or open the entrance 

 to the internal ear. 



To the Water 

 vShrew Mouse this 

 structure is probably 

 of some service, for 

 by means of it he 

 can effectually pre- 

 xent the water enter- 

 ing his ears when he 

 di\'cs ; but it is more 

 difficult to estimate 

 its utility in the case 

 of our two land 

 Shrew Mice, and I 

 hax'e not been able 

 to deter m i n e the 

 reason why a land 

 Shrew Mouse prefers 

 at one time to keep 

 his ears wide open, 

 while at another time 

 he prefers to keep 

 the m hermetically 

 sealed. 



In all our three 

 species of Shrew Mice 

 the hair is of similar structure to that 

 of the Mole. 



The \-elv^et softness of the Mole's fur is 

 ])robably familiar to most of my readers. 

 The fur of a Common Shrew Mouse in 

 good condition is softer still, while that 

 of the ]\vgmy is the softest fur known to 

 me. It is fortunate for him that his skin 

 is (jf a corresponding delicacy, and that 

 it would take many thousancls of him to 

 make a fashionable garment. But soft- 

 ness is not the only ])eculiarity of Shrew 

 Mouse fur. The pelage of the Pygmy 

 Shiew Mouse (and of the immature 

 Common Shrew Mouse) displays an iri- 

 descence which has been comimred to 

 watered silk or to the gorget of a hum- 

 ming bird. To my mind, howe\-er, the 

 iridescence is of a less blatant character, 

 and can be more reasonably compared 

 to the bloom on certain fruit. The 



