294 ^^^^^^ Life 



C. viridis, yet by attention to three points it may 

 as easily be distinguished: the eigJd rows of cerata 

 are more distant, except the first three rows which 

 are close, the head and shoulders are sprinkled with 

 opaque white raised points, and the back and cerata 

 are dotted with dark brown. The Olive ^Eolis 

 (G. olivacea) is also greenish, but, as the names in- 

 dicate, dull brownish green. The body is yellowish 

 white, dotted with opaque wdiite, and stained about 

 the head with rosy streaks and a big blotch of the 

 same tint. 



The Despised ^Eolis (Tergipes despectus) is a minute 

 creature, only about a third of an inch in length, 

 but except on tliis ground in no way deserving its 

 name. The foot is transparent and colourless, to let 

 the colour of the Laininaria on which it glides show 

 through. There are only four cerata on each side, 

 and these are arranged alternately, not opposite as 

 is customary in the family. The head and shoulders 

 are streaked with rose colour, and this extends up the 

 tentacles, and often along the sides of the foot. The 

 digestive track is clearly seen through the back, 

 coloured with pale olive or yellow-brown, taking a 

 bold zigzag course and sending out a branch at each 

 angle to one of the cerata. The centre of these is 

 similarly coloured, but the tip is opaque white, and 

 the intervening transparent band sometimes red. It 

 feeds upon the Hydroid Ohelia genicidcda, or upon 

 the minute algae which grow upon its stems. Ohelia 

 is abundant on the fronds of some of the large Oar- 

 weeds, and as T. despectus crawls about them, and the 

 colour of the weed shows through it, little but the 

 digestive track and the connected cerata can be seen : 



