56 



Uiis lime the anterior edge of the fuiiiie] curves inwards, 

 and so causes the funnel aperture to become almost 

 completely closed (PI. II, tig'. 7a, /. cl.). In this sketch 

 it will also be seen that the anterior mantle slit is now 

 widely opened, to allow the water to pass inward (m.op.). 

 Inspiration is accompanied by a slight movement upwards 

 and backwards of the whole body. During expiration, 

 the walls of the body contract again, as the amount of 

 water contained in the mautle cavity becomes greatly 

 diminished. This water is, however, bound to go out by 

 the anterior funnel aperture (fig. 76, f.op.), for this is 

 now wide open while the mantle slit is tightly closed by 

 the locking apparatus (fig. ~ib, m.cl.). With expiration 

 the body moves slightly downwards and forwards. When 

 a stream of borax carmine was passed in at the mantle 

 aperture, during inspiration, it was passed out again as a 

 red jet, from the anterior funnel opening, during 

 expiration. Thus the way the respiratory water passes 

 was indicated. The stream of water thus ejected is sent 

 out with great force, and disturbs the surrounding water 

 for a considerable distance. There appears to be no 

 constant rate of respiration. After a period of rest, say 

 in the early morning in an aquarium, the rate is some- 

 times as low as six per minute, while after agitation it 

 increases to sixteen per minute. During the daytime it 

 averaged twelve to fourteen. Smaller specimens appear to 

 breathe rather more rapidly than larger ones. While 

 resting, the tip of the funnel is generally seen protruding 

 either from below the right or the left side of the 

 body (Text fig. 1). Every now and then Eledone 

 changes the funnel over from one side to the other, and 

 while so doing the respiratory movements slacken 

 considerably. Often the body will be noticed to heave 

 convulsively, and the respiration to quicken greatly, for a 



