EVOLUTION 135 



glance is remarkably like Barnea (Pholadida), 

 and occurs in similar situations (Plate XXXII., 

 Figs. 15 and 16). 



The reproduction of lost parts takes place to a 

 considerable extent among the Mollusca. Experi- 

 ments made in the eighteenth century by Spallanzani, 

 and fully confirmed later by Tarenne, go to show that 

 Snails can reproduce not only the tentacles, but even 

 at times the whole head, while Madame Power 

 obtained similar results so far as portions of the foot, 

 mantle, and tentacles of marine species were con- 

 cerned. The cerata of Nudibranchs it is known can 

 be reproduced, as well as the arms of Cuttlefish and 

 the siphons of Ensis and Soleairtus. In some cases 

 self-amputation can be voluntarily performed and 

 the parts reproduced. This is the case with the 

 swimming lobes of Lobigev, the hind-portion of the 

 foot of Harpa, and the long mantle fringes of Lima. 

 These last will live for some hours after separation 

 from the animal. The phenomenon has also been 

 observed among Land Snails. Thus in Cuba, 

 Gundlach has recorded that Pleurodonta imperator 

 and P. crassilabris part with the hind-portion of the 

 foot, which will show signs of animation fifty-four 

 hours after, the line of separation always occurring 

 at the same spot, and the lost part being soon re- 

 produced. The West Indian Stenopus is credited 

 with a like faculty. In the Philippines, Semper 



