PLANKTON OF THE GULF OF MAINE 
325 
and early May of 1920, and at all four of the stations on the continental slope. The 
localities for the gulf proper (fig. 90) are all from the deepest trough, as is the one 
autumn record for the eastern basin just mentioned, and most of the captures have 
been in hauls from considerable depths, as follows: 
Station 
Depth in 
meters 
Number 
of speci- 
mens 
20044 
/ 250-0 
\ 750-0 
180-140 
1 
20055 
13 
1 
20066 
60-0 
1 
20069 
1, 000-0 
9 
20074 
125-0 
5 
20076 
200-0 
15 
20077_ 
800-0 
20 
20079 
180-0 
1 
Station 
Depth in 
meters 
Number 
ofs peci- 
mens 
20081 ___ 
40-0 
1 
20086. . 
150-0 
2 
20087 
200-0 
2 
20107 
140-0 
2 
/ 100-0 
1 
20112 __ 
\ 200-0 
20013 
130-0 
2 
20015 
200-0 
3 
20129 
100-0 
2 
The single September specimen was from a tow at 130-0 meters, while the June 
specimens off southern Nova Scotia (station 10295) were from 500-0 meters. The 
reader will note that there are only two records (a total of two specimens) from tows 
shoaler than 100 meters, one of which was taken over much deeper water and may 
have been brought up from its normal habitat by some local upwelling; the other was 
on Georges Bank. 
Associated with the considerable depth of the records, we have usually found 
S. maxima in water of the relatively high salinity of 33.5 to 34 per mille, or more, 
though on the rare occasions when it is swirled up toward the sin-face it may stray 
into less saline strata of water (32.36 per mille at station 200S1; 32.6 per mille on 
Georges Bank). Its general distribution farther north, and especially its failure to 
colonize the Gulf of St. Lawrence (Huntsman, 1919), suggests that it is unable to 
survive in water of low salinity, irrespective of temperature. 
S. maxima is at home only in comparatively low temperatures. We have never 
found it in temperatures warmer than about 6.5° within the gulf, but, on the other 
hand, it usually lies below the coldest level in waters of 3.5 to 5°, the only records from 
temperatures lower than 3° being its sporadic appearances in the upper levels, in about 
1.63° at station 20081 and about 2.6° at station 20066. The captures of S. maxima 
along the continental slope have been in temperatures of 3 to 6° and salinities of 
34 to 34.9 per mille. It occurred under about these same conditions over the con- 
tinental shelf abreast of Shelburne in March, 1920 (stations 20074 and 20076). 
Occasionally, however (whether or not as a result of upwelling is not clear) , we have 
taken it in decidedly warmer water at our outermost stations; for example, in 7 to 8° 
temperature at station 20129 and one specimen in 9° or warmer at station 20044. 
In north European seas S. maxima is equally characteristic of cold but highly 
saline water layers (Apstein, 1911), and probably it is this rather precise relationship 
to the physical state of the water which bars it from the Gulf of Maine in summer but 
allows it access there in winter; for while the trough of the gulf is sufficiently salt for 
it throughout the year and cold enough — say, 5° to 6° below 100 meters — in winter and 
early spring, the bottom water may well be too warm for it in some summers if not in 
all. At such times any maxima that drift inward through the eastern channel 
8951—28 22 
