NOTES AND QUERIES. 425 



produced ; they are generally three to four, and are born blind." It would 

 be interesting to know whether this was the second litter this vear. 

 T suppose Hedgehogs are capable of producing two litters in a year, as 

 I have not heard or read to the contrary. — F. Hayward Parrott (Walton 

 House, Aylesbury). 



Distribution of the Bank Vole.— I see by your paper in 'The 

 Zoologist' for October, that you wish for localities for the Bank Vole. 

 T accordingly send you a list of the counties in which I have taken this 

 Httle animal. At Kingsbury, Middlesex, it was quite common twenty years 

 ago ; I sent some from there to the late Mr. Yarrell. The first specimen 

 I ever saw was brought to me by a favourite cat ; I have it still, and it is 

 the best specimen I think I ever saw. I have taken the Bank Vole in 

 Buckinghamshire, Berkshire, Hants (Isle of Wight), Hertfordshire, Cam- 

 bridgeshire, Herefordshire ; and I once found a dead one within a quarter 

 of a mile of Monmouth. About twenty years ago I saw a very pretty variety, 

 of a light cream-colour with red eyes, that was taken in Huntingdonshire. 

 I believe it will be found to be regularly distributed in England, if looked 

 for. — Frederick Bond (Staines). 



Black Rat in Wexford. — The Black Rat is not infrequent in the 

 neighbourhood of New Ross. I have myself met with it at Kilmanock, 

 where it can hardly be called very rare. I have also heard of it at 

 Duncannon, a village near Arthurstown, not far from Hook. — Gerald 

 E. H. Barrett-Hamilton (Harrow School, Middlesex). 



The Musk Rat and the Unio. — There has been much discussion in 

 regard to the method by which the Musk Rat, Fiber zibethecus, Cuv., opens 

 the Unios which it uses for food, and many methods have been suggested 

 as to the manner in which the body is taken from the shell. Nearly every 

 method proposed has been based upon the strength of the adductor muscles 

 and the supposed impossibility of overcoming their power without killing, 

 or at least poisoning the animal. In experimenting with some Unios last 

 summer, I found that it was an easy matter to get the shell open as far as 

 the ligament would open it, and that in this condition it required much 

 less than a Musk Rat's strength to force it entirely open. When the Unto 

 is travelling along, its foot projects a half inch or more from the lower side 

 of the shell. If, while the foot is in this, its usual condition, the two valves 

 be pinched, the foot will be caught between the closing shells; if the pinching 

 be continued for half or three-quarters of a minute, the animal, probably 

 from the pain produced, becomes paralyzed and unable to make use of the 

 adductor muscles. Now, if the shell be released, it will fly open about 

 one-half inch, and can easily be torn entirely open. The strength needed 

 to keep the foot from being drawn into the sliell is not great, being far less 

 than that of the jaws of the Musk Rat. So all that it is necessary for 



