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Transactions of the Royal Canadian Institute 



TABLE IV. 



having been transported thither. It will have been the inflowing deep 

 current of strongly saline water that has carried them. They tend to 

 remain near the bottom at least during the bright half of the day, as 

 is shown in Table IV. This habit permits them to escape being carried 

 from the estuary by the outflowing superficial current of somewhat 

 brackish water. They should, therefore, tend to accumulate in the es- 

 tuary. This explanation is sufficient to account for the facts that have 

 been given. 



Discussion. 



In the Magdalen shallows, as at "Prince" station no. 30, Sagitta 

 elegans breeds very successfully. The picture presented in Table II 

 is a uniform one. Eggs were very numerous on May 23rd, 1917, but 

 no young had yet appeared. By May 31st hatching had begun, and 

 by the middle of June egg laying was complete. Development in the 

 egg must proceed very rapidly, as, although all stages were found on 

 June 13th, none at all were taken on the 20th, and the young had ad- 

 vanced considerably beyond the stage at which they emerge from the 

 egg. The maximum size of the young steadily increased from 4 mm. 

 on May 31st to 12 mm. on July 11th. The physical conditions of the 

 water in which there was this success in the development of the embryos, 

 in the hatching of the eggs, and in the growth of the young, were the 

 following, as furnished by Professor Vachon in advance of publication: 

 During the period when the eggs were developing the temperature rose 

 at the surface from 3.44 to 9.10°C., and at 10 metres depth from 2.40 to 

 5.09° C. By July 11th at both levels the temperature had nearly reached 

 14°C. The salinity during the whole period was quite constant, the 

 extemes being 29.61 and 30.53 0/00. The densities also varied little, 

 the range being from 1.02134 to 1.02429. 



In the Bay of Fundy, as at "Prince" station no. 3, breeding is a 

 failure. The spawning season is prolonged as compared with the 



