OA^'ADIiy FISHIFJRIHS EX I'EDITIoy , 19I',-to 



181 



51 per cent Torianus, 25 per cent Temora, 15 per cent Pseudocalanus, and per cent 

 Centropages. The temperature here fell from 12° C. at the surface to 11-45° C. ?.t 45 

 metres and the salinity was 29-14 per thousand at 20 metres. 



Table J.— Data for Acadia station 89, Misaine Bank, 1-32 metres, July 28, 1915. 



8.-35 p.m. 



Si)ecies. 



C. finmarchicus TIT 



IV 



V . . . 



9 



cf 



C. hyperboreus III 



IV 



V 



9 



Pseudocalanus elongatus. . 



Euchajta norvegica 



Centropage* hainatus 



Metridia longa 



Anunialocera patertsoni .... 

 Tortanus discaudatu.s ... 



Surface. 



2(; 

 17 



2 



5 

 4 



X 

 X 



100 



30 -Of. 



1 

 44 

 18 

 10 



3 

 15 



X 



O.T-0 f. 



3 

 34 



It; 

 « 



X 

 4 



20 

 1 

 1 



12 



X 

 2 

 1 



100 



100 



In September, 1915, Dr. A. G. Huntsman made a short cruise in the Bay of 

 Fundy in the ss. Prince, belonging to the Biological Station at St. Andrews. The data 

 for the Copepods at the four stations are given in table XII. For the first time in the 

 course of these investigations we meet with the species Centropages typicus which 

 occurs regularly in the gulf of Maine and far to the southward of cape Cod, even 

 reaching the latitude of cape Charles (Bigelow, 1915, p. 293, and fig. 70, p. 294). 



At Prince station 1, Dr. Huntsman observed a great stirring up of the water from 

 the bottom to the surface in consequence of the eddies caused by the tidal currents 

 surrounding the points of land. The presence en masse of C. finmarchicus at the 

 surface between 3 and 4 p.m. under a bright sun is unusual, and perhaps the deep- 

 seated turbulence of the water, with the resulting lack of stratification, was respoTi- 

 sible for it. It would be worth while to repeat the station, taking samples at intervals 

 through the twenty-four hours, in order to ascertain whether the diurnal migration of 

 Calanus is altogether inhibited. The effect of stratification of the water, so far as 

 temperature is concerned, is seen in an experiment by Dr. G. H. Parker (1902). 

 Female Lahidocera are negatively geotropic, and remain at the top at all temperatures 

 between 10° and 26° C. If the temperature is raised to 30° C. they become positively 

 geotropic and swim to the bottom. The lower half of a large glass tube was filled with 

 sea-water at 24° C. ; into the upper half sea-water at 30° C. was poured gently. A 

 female Lahidocera, introduced at the top swam rapidly downward, but stopped at the 

 plane of separation for the two temperatures. 



Besides the diurnal and seasonal migrations of Calanus to which reference has 

 been made, there is another kind of translation which has been called ontogenetic 

 migration by Dr. Giesbrecht. Some pelagic copepods, as Clauso calanus, Pseudocalanus, 

 Eucha^ta, Eurytemora, carry their eggs in an ovisac attached to the genital segment, 

 but most species discharge their eggs directly into the sea. These eggs, according to 

 Giesbrecht's observations, have a somewhat higher specific gravity than the water and 

 consequently sink slowly; whilst they are sinking they accomplish their embryonic 

 development. As soon as the Nauplius larva hatches out of the egg, it ascends toward.s 

 the surface and towards the light, all copepod Xauplii being positively heliotropic. 



