250 LIFE BY THE SEASHORE. 



little creature, chiefly remarkable for its strange contortions 

 and quaint shape. 



So variable is the shape that the animal is not easy to 

 describe. There is also considerable variation in colour; 

 when young the whole animal is violet or purplish, while in 

 the adult state it is greenish grey, speckled and mottled 

 with brown and white. The shell is not visible externally, 

 and the body is dome-shaped, the slender head projecting 

 markedly in front. There are two pairs of tentacles, of 

 which the upper (t) are shaped like hares' ears, and bear 

 the small eyes at their bases. At the sides of the body two 

 large flaps, or epipodia (ep in Fig. 71), rise straight up, and 

 almost meet in the middle line of the back. If you fold 

 back the epipodium of the right side you will see behind it 



the single gill, and 

 the curious grape- 

 t shaped gland 

 which secretes the 

 purple fluid. Be- 

 tween the epipodia 

 in the mid-dorsal 

 line lies the thin, 

 papery shell, al- 

 most entirely 

 covered by the 



After Gosse. mant l e . The foot, 



as usual, forms a creeping surface, but both it and the 

 epipodia are very contractile, and in life are constantly 

 changing shape. When the animal is actively crawling, 

 the foot projects considerably behind the body. Such an 

 expanded specimen may measure from two to four inches 

 from tip to tip. Between the epipodia on the dorsal surface 

 there projects a siphon-like process of the mantle, which 

 leads from the anus to the exterior. On dissection it is 

 easy to find the heart lying in front of the gill, the curious 

 horny jaws in the mouth, and the gizzard armed with horny 

 plates. 



The next genus we shall consider is the very large one 

 of Doris, including the true sea-slugs, or sea-lemons. By 

 recent authors this genus has been broken up into a large 

 number of small genera, but as we shall only consider some 



