252 LIFE BY THE SEASHORE. 



brown on a ground colour of yellow or white. The dorsal 

 tentacles are short and broad, and there are also a pair of 

 slender oral tentacles at the sides of the mouth. There are 

 fifteen tripinnate gills. 



The next species is much more beautiful and much 

 smaller. It is called Doris repanda, is usually about an 

 inch long, and is of a dead-white colour, with a row of 

 yellowish white spots down each side. The back is covered 

 with indistinct rounded tubercles, and there are only five 

 small gills. The oral tentacles are broad and flat and the 

 dorsal ones long, Like most of the smaller species, this 

 one can take advantage of the surface tension to creep along 

 the surface of the water back downwards, and is then a 



FIG. 72. Doris johnstoni. Note the gill-plumes and the dorsal 

 tentacles. After Alder and Hancock. 



beautiful little object. The actively moving tentacles, the 

 delicate branched gills, and the translucent whiteness of the 

 tissues, make it a delightful occupant of an aquarium, but, 

 like most of the Dorids, it requires some care in confinement, 

 being apparently very sensitive to impurities in the water. 

 It is not uncommon under stones on the shore. 



Another species is Doris bilamellata, which occurs in the 

 Firth of Forth in February and March in countless numbers. 

 It is no exaggeration to say that in these months the rocks 

 are simply whitened by these little creatures and their 

 spawn. They are not particularly pretty, and show no 

 brightness of tint as so many inedible or noxious insects do, 

 but seem to enjoy immunity from persecution to a very 

 marked extent. I have not found any shore animal which 

 will eat them, and even the sea-gulls seem to leave them 



