214 NATURAL HISTORY OF OUR SHORES 



half wide, and is beautifully frilled, and coiled with one 

 edge to the rock, exactly like a rosette. 



If a portion of one of these ribbons is taken when the 

 young are just hatched (which can be known by the ribbon 

 beginning to break up), and viewed under the microscope, 

 a beautiful sight will present itself. 



The capsules are closely set in the ribbon, and within 

 each there are three, four, or five young. Each has a 

 beautiful, transparent little shell of nautilus shape, and 

 the portion of the little animal which projects is ciliated. 

 These young are very active, and by the action of their 

 cilia swim round and round within their little prison, the 

 whole looking like a bewildering bit of mechanism. A 

 rough idea of this arrangement, as seen under a low power 

 of the microscope, is shown in Fig. 92. 



The presence of a shell in the young is interesting, as it 

 points to the descent of the nudibranchi from shell-bearing 

 ancestors. 



Another Doris, less frequently met with than the above, 

 but sometimes occurring abundantly, is Doris pilosa. This 

 is only about an inch long, of a pure white, and the skin is 

 covered with minute, velvet tufts. 



Other forms present on our coast are Doto, Dendronotus. 

 and Eolis. In the first two the branchial organs are 

 branched, in arborescent fashion, along the back. In 

 Eolis they are in leaflike papilla?, and part of the digestive 

 system is situated in them. 



The commonest species of the latter genus is Eolis 

 papillosa. This is sluglike, of a yellowish white or a pale 

 grey colour. It is about two inches long, and when not 

 in motion, but with head and tentacles retracted, it could 

 easily be mistaken for some kind of anemone. It feeds 

 chiefly on anemones, taking a meal off the living mass 

 and passing on. It is the only animal I know of 

 that preys on these. It deposits its eggs in threadlike 



