Quarterly Journal of Coiichology. 1 8 1 



found only one individual. Dec. 31st, temp. 26° — None to be seen. 

 The frost continued without intermission throughout the first week 

 of the new year, during which time on the occasion of two visits to 

 the same and neighbouring spots I failed to find it about, nor could 

 I discover any at the roots of the Luzula. Jan. 9th — Milder. 

 H. fusca again abroad, and more abundantly on the loth. 



It appears then that a continuance of a temperature below freez- 

 ing-point for six successive days was necessary to drive to its retreat 

 a mollusk protected by a shell so thin as to be almost membranous, 

 and that on the slightest return to warmer weather, the circulation 

 of the animal sufficiently increased to enable it to resume activity. 

 I unfortunately neglected to note the number of pulsations of the 

 systems per minute. 



It is somewhat singular that another thinly-clad snail, Vitrina 

 pcllucida, — a tenant, by the way, too large for the house it occupies 

 and therefore still less protected than Il^lix fusca — ^retires from 

 only severe cold. It may be found almost any part of the winter 

 during mild weather and I have noticed it even crawling over frost- 

 covered leaves. I want to know more about If. fusca and shall be 

 glad to compare notes with other observers as to its winter habits. 

 Is it usually the case that it does not hybernate for the season? 

 Upon what plants does it generally feed? When it retires, does it 

 bury itself, or remain near the surface? Though very generally 

 distributed (according to our authorities) I must confess to having 

 met with it in only two localities. I hope some of your corres- 

 pondents will record in your pages the result of their observations 

 of this species. 



NOTE ON THE SYNONYMY OF PLANORBIS 



GLABER, (Jeffreys). 



By \Vm. nelson. 



In 1840, Dr. J. E. Gray — in his work" entitled " A Manual of the 

 Land and Freshwater Shells of the British Islands " — speaking of 

 P. loevis. Alder, remarks upon its similarity to P. parvus, Say. 



