Reproduction in Sagitta Elegans 1,Q9 



found not only over the open bay, but also far up the estuaries, pene- 

 trating into waters where the adults are not to be found, at least during 

 the summer. 



At "Prince" station no. 21, in Kennebecasis bay, an arm of the St. 

 John river, situated a considerable distance above the reversing falls, 

 young individuals were taken in September, 1916, in the deeper wate^, 

 Vachon gives the salinity of this water as from 18 to 21 0/00 (1918, 

 p. 323). Unfortunately all the surface water samples taken at that time 

 were lost through freezing, but the surface water appeared to be entirely 

 fresh. In this bay many miles from any know^ habitat of the adults at 

 that time of the year, young Sagittae were to be found in the brackish 

 water underlying the fresh water of the surface. As the Sagittae were 

 more abundant toward the mouth of the bay and occurred in the river 

 connecting the Kennebecasis with St. John harbour and the Bay of 

 Fundy, it is at least probable that all the individuals in the Kenne- 

 becasis had been carried in from the Bay of Fundy either as eggs or young. 



The general observation has been made in recent years that young 

 Sagittae are more plentiful in the estuaries than in the open Bay of Fundy, 

 and that in the latter they are more plentiful where distance from land 

 and shoals permits stratification of the water as at station no. 3, than 

 where the proximity of land and shoals ensures constant mixing as at 

 station no. 5. In the spring of 1920 an opportunity was afforded for 

 determining the distribution of the young Sagittae in a rather long narrow 

 estuary, the Magaguadavic river. This river empties into Passama- 

 quoddy bay, and in its tidal portion a constant mixing of fresh and salt 

 water takes place with the transition from one to the other not very 

 abrupt. Four stations were established in this estuary, one at the mouth 

 ("Prince" station no. 158) one at the head of tide (no. 161), and the re- 

 maining two in between. On June 19 at high tide tows with a net of 

 no. mesh were taken at the surface and near the bottom at all of the 

 stations. On June 21 at low tide similar tows were taken at all stations 

 except the uppermost. The Sagittae obtained in these tows are given in 

 Table IV. From a consideration of these results it will be evident that 

 at high tide the majority of the Sagittae were to be found in the middle or 

 upper portion of the river, and that at low tide they had shifted down to 

 the lower half. 



The deduction might be made that this intermediate water of some- 

 what low salinity and high temperature is more favourable for the 

 survival of these animals through the period of embryonic and early 

 adult life than is that of the bay. Another explanation must not be 

 neglected. The presence of the Sagittae in this estuary a number of 

 miles from the habitat of the adults is prima jade evidence of their 



