PROGRESS IN BIOLOGICAL INQUIRIES, 1926 020 
Bay does not maintain the supply of fish in that area, and that in 
all probability the inshore spawning grounds north of Cape Cod, as 
a aks are not selfsupporting but must rely on immigration from 
other areas. It is to be expected that some of the cod eggs that 
drift west into the Gulf of Maine will hatch before they leave the 
bay; but this probably does not alter the situation in any way, for 
the current that carries them in will transport them out again. A 
report on this work will be submitted in the near future. 
Biological collections from the region of the Grand Banks supple- 
ment, to a surprising degree, the hi etd al observations made 
by the Ice Patrol on the currents in that area. Each of the three 
principal water masses of the region—the liabeade current, Gulf 
Stream, and “banks water ”—is characterized by its own particular 
pelagic faunas and can often be defined as accurately by net collec- 
tions as by temperatures and salinities. 
In 1921, a series of hauls taken over the zone where the Labrador 
current and the Gulf Stream meet indicated clearly the sharp line 
of demarcation between the Arctic and the Atlantic faunas. The 
present investigation is limited to the area east of Newfoundland and 
is concerned with the meeting of the Labrador current and the third 
great mass—the “ banks water.’ 
The reports of the Ice Patrol have shown that a large drift of 
coastal water moves east from the vicinity of Cape Race and spreads 
over the whole region of the Grand Banks except the northeastern 
part. The plankton collections indicate clearly the faunal differ- 
ence in these two water masses. The most northerly station yielded 
a true Arctic community, but the more southerly ones, along the 
western margin of the banks, were of a boreal coastal nature, 
although far ‘from land. 
It may be that the Grand Banks are not dependent entirely upon 
local production to maintain their supply of bottom invertebrates 
(fish food) but are constantly enriched by an influx of the pelagic 
young of species from the coast, which, sinking to the bottom, find a 
favorable environment in the comparatively shallow water of the 
banks. If this be true, and both the hydrographical and biological 
evidence support it, the Grand Banks are unique among fishing 
grounds in that an ‘offshore drift continually adds to the resident 
bottom invertebrate community upon which the cod feed, while two 
great ocean currents transport enormous quantities of microscopic 
plants and animals, which, killed in the mixing zone of the sudden 
temperature changes, sink to the bottom and insure a rich source of 
nourishment for the crabs, upon which the fish feed. 
In the course of the investigation several interesting minor obser- 
vations were made. A great difference was found in the size of 
cod eggs from Massachusetts Bay and those from the region of the 
Grand “Banks, the former averaging 1.5 millimeters and the latter 
1.28 millimeters. The cod eggs collected in the region of the Grand 
Banks on June 5 to 17, 1924, ranged from 1.1 to 1.55 millimeters, and 
averaged 1.28 millimeters. 
‘These eggs were found to average between 1.2 and 1.3 milli- 
meters everywhere except at the most northerly station (approx- 
imately 390 miles north of the tip of the Grand Banks), where 
a surprising average of 1.42 millimeters was found, no eggs being 
