Ashford: the action of the heart in the helicid^. 323 



Many difificulties occur in the way of observation during the 

 actual hibernation of the animal. Some species have shells too 

 opaque to allow of the heart's action being detected through that 

 envelope, and I have already pointed out a great objection to the 

 removal, even of a part, of the shell; other species with fairly 

 transparent shells are difficult to procure in winter, and oppor- 

 tunities are rarely afforded for convenient observation from day to 

 day of the same mdwidi/al -without transferring it to a fresh locality 

 nearer home, where conditions may not be perfectly natural. 

 From these causes it is probable that a long time will elapse before 

 we obtain exact general knowledge of the condition of the Helicidae 

 during their dormant stage. 



In late autumn of 1881, however, I found a single individual 

 of N. hortensis and two or three of Z. cellarins in hibernation at 

 the base of Vinca major on a rockery in the garden, and well 

 positioned for easy inspection. Fixing a thermometer at the spot, 

 I made comparisons of pulse and temperature during the months 

 of December, January and February at suitable intervals. The 

 following are some of the results in the case of H. horte7isis. 

 The upper numbers give the temperature Fahr. at the time of 

 observation (generally about 9 a.m.), and the numbers beneath 

 them the corresponding pulse rate per minute. 



Temperature 42, 33, 29, 44, 38, 37, 40, 38, 43, 41, 31, 30, 26, 43, 52. 

 Pulse 14, 5, 3?, 14, 10, 9,10, 9,14, 9,3?, 4,3?, 8,22. 



In three instances a mark of doubt is added. The animal, 

 under the influence of the low temperature, had withdrawn itself 

 rather further into its shell, so that the heart took up a position 

 just within the epiphragm, and, though perceptibly in motion, it 

 was not sufficiently in view to leave the numbers clear of doubt 



