260 LIFE BY THE SEASHORE. 



of the resemblance to coralline, nor do I know what animals 

 attack it under natural conditions. 



The next set of sea-slugs we shall consider belong to the 

 very large genus Eolis (see Fig. 76), whose members often 

 chiefly differ from one another in colouring, and are usually 

 exceedingly beautiful. All are characterised by the simple 

 slender papillae arranged in rows or clusters at the sides of 

 the back. Most of them live among weeds and zoophytes, 

 on the latter of which they chiefly feed. We shall consider 

 here only a few of the commoner species. 



The common grey sea-slug (Eolis papillosd) is the largest 

 of our species, and may reach a length of three inches, but 

 is usually much smaller. The middle of the back is perfectly 

 smooth, and in small, delicate specimens it is easy to see the 

 beating of the transparent heart through the skin. The 

 sides of the body are densely clothed with closely set 

 papillae, arranged in more or less distinct rows, and usually 

 greenish or brown in colour. As in the other species there 

 are two pairs of tentacles a dorsal pair, here short and 

 stout, and a ventral or oral pair beside the mouth. The 

 colours are variable, but usually not bright, and the papillae 

 so frequently fall off in confinement that the animal is 

 hardly a desirable occupant of an aquarium. From its 

 large size it can be dissected more readily than many of 

 its allies, and dissection will disclose the curious fact that 

 the stomach is much branched, its branches being continued 

 into the papillae. 



The next species is much more beautiful, and is fairly 

 common between tide-marks on the North-east Coast. It 

 is called Eolis coronata, and is usually less than an inch 

 long. The body is proportionately much more slender and 

 elongated than that of the preceding species, and the 

 papillae are arranged in transverse rows across the back 

 instead of in dense masses at the sides. The dorsal tentacles 

 are what is known as "coronated," being surrounded by 

 spiral yellow projections of very characteristic appearance. 

 The oral tentacles are very long and slender, and the anterior 

 angles of the foot are produced. The body is a delicate 

 pinkish white colour, but it is to the papillae that the 

 animal owes its beauty. They are transparent, and traversed 

 through the greater part of their length by the branches of 



