476 DEFART3IENT OF THE NAVAL SLRTICE 



Vertical. — At station 23 of the cruises of tlie trawler No. 33, three vertical hauls 

 were made frora various depths with the closing net. This station is well up in the gulf 

 of St. Lawrence, and so well away from places, where mixing is going on which might 

 through vertical currents vitiate the results. Six specimens of this species were 

 obtained between 340 and 145 metres, and none between 100 and 60 metres and from 

 45 metres to the surface. On the cruises of the Princes^ in the gulf, numerous hauls 

 were made in the deeper parts with open vertical nets from 100 or 130 metres, and at 

 only one station was this species obtained. Its vertical distribution for the gulf may 

 be considered to lie below 130 metres. 



In the Bay of Fundy at station 3 of the Prince, two specimens were obtained in 

 the open vertical net from 180 metres and none in the tows above 20 metres in depth. 

 Yet at station 1, although none were obtained in two open vertical hauls from the 

 bottom (showing the rarity of the &i)ecies there), three specimens were obtained in the 

 tow haul about 20' metres in depth and one in a haul made at the surface. This latter 

 station was in the Friar Roads between Eastport and Campobello island. The tides 

 here are of such magnitude that the water forms whirlpools and the " boiling "' up of 

 the deep water to the surface can be seen constantly. These vertical currents are 

 certainly responsible for bringing this deep-water species to the surface at this point. 

 Jiist outside Campobello island at station 2, both the vertical haul from about 100 

 metres up and the tow hauls failed to secure any specimens of this form, showing that 

 it was some distance down. 



Its presence at or near the surface at Acadia stations 15, 16, 25, 26 and 27 indicates 

 that there were strong vertical currents at the mouth of the Laurentian channel on the 

 first cruise of the Acadia. On the second cruise it was at or near the surface only at 

 stations 77, 85, 86, and 87 at the mouth and some distance up the Laurentian channel- 

 showing strong vertical currents in about the same area. The data from the last three 

 stations are interesting. At stations 85 on the north side of the channel, where S. 

 serratodentata and S. maxima were most abundant, we find this species coming near the 

 surface in fair numbers (20-10? metres, rather many) and many obtained in both the 

 shallow and deep vertical hauls. At 86 in the middle of the channel, while very many 

 were obtained from both vertical hauls, only one was seen in the material taken by the 

 tow haul. At station 87 on the south side of the channel, while a fair number came up 

 in the deep vertical haul, the shallow vertical haul yielded five only, and a solitary 

 specimen was observed in the tow. This species comes aiearer to the surface as we pass 

 to the north across the channel, indicating greater vertical currents on the north side- 

 or a greater influx of the cold deep boreal water, from which the vertical currents may 

 bring the species to the surface. There is, of course, the possibility of the species 

 coming to the surface of itself under changed conditions, perhaps of salinity and 

 temperature, as it does in polar regions. 



The vertical distribution seems to vary with the region, but these details may 

 more appropriately be considered in connection with the horizontal distribution. 

 Suftice it now to say that it did not appear in the outer and southern stationsi (stations 

 41 to 46, 56, 75), the hauls, one of which was fi-om a depth of 375 metres, apparently 

 being too shallow, the cosmopolitan distribution of the species making it fairly certain 

 that it was present but at lower levels. Fowler (1906, p. 73) refers it to the epiplank- 

 ton (usually young specimens) north of 47° IST., and to the ^nesoplankton in tropical 

 and sub-tropical waters. Michael (1913, p. 35) states that his data suggest " that the 

 region of maximum abundance is in the neighbourhood of 250 fathoms for the San 

 Diego region." 



The records are too fragmentary to show whether or not daylight affects the 

 vertical distribution. 



Horizontal. — This species is cosmopolitan, being found in all seas, and it extends 

 to both tliei farthest north and the farthest south- As it is a deep-water form in low lati- 

 tudes, if we consider only the proper layers of the sea (the part explored by our nets), 



