142 THE ROYAL SOCIETY OF CANADA 



the reproductive elements, after which they gradually sink to the 

 bottom. 



In the Echinoderms it is common to find certain species in much 

 shallower water in the early spring than at other times of the year. 

 Among the starfish, Mediaster œqualis and Orthasterias leptolena are 

 found on the rocks that rise more or less vertically at or above low 

 water mark, but later on in the summer they can be got only by dredg- 

 ing. Some of the others do not show such migration. The commonest 

 of all, Pisaster ochracea, may be found at or above low water at all 

 times of the year. Brittle stars are found at various depths, but no 

 definite migration has been observed. The purple sea-urchin, Stron- 

 gylocentrotus franciscanus, comes up to shallow water, even above 

 low tide, in the early spring, but later after the eggs have been shed 

 takes again to deep water. Among the Holothurians, Stichopus, at 

 least, has much the same habit as the purple urchin but others do not 

 appear to have the same migratory movement. In the Crinoid species, 

 Florometra serratissima, that is so abundant in this vicinity, the 

 larvae become attached to the adult so there is little chance of much 

 distribution afield, even in the early stages, and the adult comes in the 

 sedentary class. 



Brachiopods, Phoronids and Bryozoa are all included under the 

 stationary forms. Rotifers appear in great abundance at times and 

 at others are entirely absent. There may be a periodicity with 

 their appearance as well as with that of the Chaetognaths but observa- 

 tion has been insufficient in either case to form the basis for any 

 statement. 



Of the Ctenophores, Pleurobrachia bachii appears in great abun- 

 dance near the surface in July and August but later in the season and 

 particularly during the winter months none are to be found. 



Among the Cœlenterates, the Scyphomedusae are most strongly 

 represented by Aurelia, which is plentiful in Departure bay from 

 October until the end of the year. During this period the eggs become 

 ripe and are shed. During the remainder of the year they are not 

 plentiful although some of them may be found at almost all times. 

 In some other localities, e.g., Nanoose bay, Oyster harbour and Saanich 

 arm, they are more abundant even than in Departure bay, so much so 

 that they give the appearance of shoal water. Of the Hydromedusse, 

 Gonionemus is plentiful among the eelgrass in shallow water during 

 May and June but is seldom seen during the remainder of the year. 

 On the other hand, ^Equorea may be seen at any time of the year 

 swimming backward and forward with the tidal currents in such 

 places as Dodds narrows where the tidal currents are strong. 



