456 Zoological Society. 



2. Some observations on Myodes Hudsonicus and the other 



species of the genus Myodes. By J. E. Gray, Esq., F.R.S. 

 etc. 



The Governor of the Hudson's Bay Company having kindly sent to 

 the British Museum the extensive series of Mammalia, Birds and 

 Fish collected by Dr. J. Rae in his late very interesting journey, I 

 have been induced to lay before the Society some remarks on the 

 species of the genus Myodes, which I hope will tend to elucidate the 

 history of these interesting animals. 



Myodes Hudsonicus has been distinguished as a species by the large 

 size and peculiar form of the claws on the front feet ; but the speci- 

 men contained in this collection appears to prove that these large 

 claws are only found in some individuals, or more likely in only one 

 sex, and that the .other individuals or sex have small, curved, sharp 

 claws, like the typical species of the genus ; and this also appears 

 to be the case with Myodes helvolus, Richardson, for one specimen in 

 the collection has the small typical claws which Sir John Richardson 

 assigns to the species, and the other has very large, thick, rounded, 

 bluntly truncated claws on the fore-feet, which is probably the cha- 

 racter of the males. 



The species of the genus in the British Museum may be thus di- 

 vided : — 



I. The upper cutting teeth narrow, smooth, without any longitu- 

 dinal grooves. Thumb with a compressed, curved, acute claw. 



a. Claws of fore-feet simple, curved. 



M. Lemwus, two specimens ; Sweden. 

 M. helvolus, Richardson, one specimen. 



b. Claws of fore-feet of some (males ?) specimens compressed 

 above, with a round, dilated, expanded pad beneath. 



M. Grcenlandicus . Fur with a dorsal streak. 



c. Claws of fore-feet of some (males ?) specimens very large, 

 compressed, strap-shaped, and with a deep triangular notch 

 at the end. 



M. Hudsonicus. 



II. The upper cutting teeth broader, with a central longitudinal 

 groove ; claws of the thumb strap-shaped, truncated, and notched at 

 the tip. 



M. helvolus, Rich. Claws of some specimens (males ?) thick, 

 subcylindrical, curved, truncate. 



M. trimucronatus , Rich., two specimens. Claws of both speci- 

 mens similar, acute, curved. 



3. Description of a new species of Anatifa. By J. E. Gray, 



Esq., F.R.S. etc. etc. 



In the collection of my friend Mr. Joseph Fryer, of Whitley House, 

 Northumberland, I have observed a very interesting new species of 

 this genus, which was given him by Mr. Hewitson, who found it at- 

 tached to a Gorgonia in Madeira. 



It is interesting as having the solid, thick, ventricose valves of 



