[fraser] migrations OF MARINE ANIMALS 141 



mais disappear. Some of them at least swim about actively in the 

 sea and may be seen thus during the rest of the year. Cephalopods 

 are found at different depths but observations have not been suffi- 

 ciently connected to establish the presence or absence of periodic 

 migration. Squid have been found cast up on the beach alive in 

 October and November, but on the other hand masses of eggs have 

 been hauled out by the shore seine in March. Very young specimens 

 have been found in the plankton in the spring and others slightly 

 larger have been dredged at various depths. 



Among the free-swimming crustaceans more attention has been 

 paid to the diurnal movements than to seasonal migration, but 

 evidence of the latter is not lacking. Of the free-swimming Ento- 

 mostraca only the copepods are numerous. In the vicinity of the 

 station very few of these are found in the plankton taken at or near 

 the surface during the winter months. Towards the end of February, 

 or early in March they become plentiful and almost as soon as they 

 appear in numbers, eggs and larvœ are also found in the plankton 

 and these may be found with the mature copepods right on through 

 the spring and summer, different species numerous at different times 

 of the year as well as different species at different times of the day. 

 Among the Malacostraca migration is very evident in the Schizopods. 

 In many cases these come to the surface to shed their eggs in such 

 large numbers during the spring that the water is colored pink so as to 

 be noticeable some distance away. They form the main portion of the 

 pink feed that supplies the different species of salmon and other fish 

 with much of the nourishment that produces such rapid growth. 

 Even whales thrive on it. Of the Decapods some of the shrimps 

 apparently inhabit shallower water in the summer months than in 

 the winter months and at least two species of crabs. Cancer magister 

 and C. productus, are often left dry at low tide when they are mating. 

 The shallow water period of many of the Amphipods and Isopods 

 corresponds very well with that of the Decapods. 



Of the marine annelids, many of the Polychgetes that live most of 

 their lives along the shore or at the bottom of the sea, come to the 

 surface to shed their eggs. In this vicinity swarming has not been 

 observed in very many forms, but in one species, Odontosyllis phos- 

 phor ea, it has induced considerable attention. Under ordinary 

 circumstances Odontosyllis is found on rocky bottom at a depth of 

 from 15 to 30 fathoms, but for the purpose of reproduction it comes 

 to the surface just after sundown in the summer evenings when the 

 water is calm and swims with the tidal current with a wavy, wiggling 

 motion. This motion in many individuals brings them to quiet 

 water where two currents meet. Here they circulate to throw out 



