442 



DEPARTMENT OF THE XAYAL SERVICE 



It extends farther to the north than anj" of the other epiplanktonic warm water 

 forms. In our area, too, it extends farther inshore than any of the others, being able 

 to withstand the lower temperature and salinity better. It seems to be equally at home 

 in the Gulf Stream and in the cold boreal water next the banks. It grows to a much 

 larger" size in the latter, but this difference can scarcely be used for dividing the 

 species into two groups. The presence of individuals above 15mm. in length is 

 indicative of the presence of boreal water, but the presence of small individuals is 

 not necessarily indicative of the presence of Gulf Stream water. Small sexually 

 mature individuals might be indicative of Gulf Stream water, but I have not correlated 



Fig. 5. ^Distribution of S. serratodentatu. May- June 1915. The zones indicate frequencies of 1 to 2r), 



26 to 100 and 100 and over per station. 



distinct from the cold bank water. Fig. 5 shows its distribution during the first 

 cruise of the Acadia. It is virtually confined to the deep water off the continental 

 shell, passing upwards over the banks only at stations 5 and 6 on the lower part of Sable 

 sexual maturity with size in my records. Taken as a whole the species is indicative 

 of the extent to which oceanic water (either Gulf Stream or boreal) extends, as 



