322 ashford: the action of the heart in the helicid^. 



necessarily attendant upon such treatment might of itself induce 

 renewed pulsation. 



From observations which will presently be detailed I think 

 that the broad statement that the heart remains motionless 

 throughout hibernation needs modification. 



Hibernation is of two kinds, complete and partial. Such 

 snails as excavate a special domicile in which to pass the winter, 

 and some of those which merely resort to natural cavities for 

 protection, probably retire once for all and do not make their 

 reappearance till mild spring weather has set in. As examples of 

 this class (I refer solely to their practice in this country) may be 

 mentioned: Helix pomatia and perhaps H. aspersa, H. nemoralis 

 and H. arbustoruni. But there are several species — acknowledged 

 hibernants — which retire in autumn, but reappear again and again 

 in the milder intervals with which our winters are diversified. 

 During these periods of resuscitation the pulsations of the heart 

 are accelerated in obedience to the risen temperature, and the 

 nutritive organs sometimes resume their functions. Thus, not to 

 mention Vitrina pellucida and Helix fusca, which can scarcely be 

 said to hibernate in an average English winter, I have noticed in 

 active motion H. sericea in December and January with a pulse 

 at 17; H. caperata apparently feeding in January and February, 

 H. hortensis in December, and H. hispida in February, pulse 3 6, 

 the same species in January, pulse 20; H pulchella in January, 

 pulse 34, another year in January, pulse 35; Cochlicopa lubrica in 

 December, and Zonites alliaritis in December, pulse 20, later in 

 the same month, pulse 14, and again in January, pulse 15; Z. 

 nitiduliis in January, pulse 1 1 ; young of H. rufescens in February, 

 pulse 26; Z. cellarius va. December, pulse 14; another individual, 

 pulse II — Bulinius acutus — in December and February. These 

 are evidently partial-hibernants. 



J.C, iii., July, 1882 



