72 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
coincided with a decided rise in the salinity of the surface water — 
(Plate 2). On the other hand Mnemiopsis, together with a few Ae- 
quorea, Cyanea, and Pleurobrachia, was again numerous at this Sta-_ 
tion, and there was a great increase in the number of Salpae (p. 275), 
which were but sparsely represented at the stations off the mouth of — 
Chesapeake Bay. The hauls at Station 10079 likewise yielded such 
oceanic genera as Doliolum, Criseis, and Firoloides. Immediately 
north of Delaware Bay (Station 10080) we once more found swarms — 
of small Salpae (p. 275) and Mnemiopsis, the nets coming in full to 
the brim. But both of these genera must have been limited to a very 
shallow surface zone, because a net working about a fathom down 
caught very few of either. Deeper down, about ten fathoms, the water 
was occupied by a swarm of Pleurobrachia. Stations 10080 and 10081 
illustrate how much more varied the plankton was near shore along 
this part of the coast than in the Gulf of Maine, for no Pleurobrachia, 
and very few Mnemiopsis were taken at the latter only about forty 
miles north of the former and about the same distance from land, with 
about the same temperature and salinity. But the deeper water 
layers must have swarmed with small Salpae, for the haul at ten fath- 
oms yielded a perfect Salpa soup; and the surface hauls caught great 
numbers of Callinectes larvae,’ which were not represented at all at 
Station 10080. 
By August 1, Salpae, which were first met in numbers off Barnegat, 
on the voyage south, had spread northward as far as the Hudson 
trough (Station 10082) where they formed the bulk of the surface tow. 
But the haul at twenty fathoms yielded very little except Pleuro- 
brachia. When the shore of Long Island (Station 10083) was ap- 
proached, the Salpae, and the Pleurobrachia swarm, were replaced 
by a rather scanty copepod plankton. 
The remainder of the work was carried on in the Gulf of Maine. 
And no sooner had the GrampPus rounded the southern angle of Cape 
Cod (Station 10085) than the boreal plankton, with which we are 
familiar from previous work in the Gulf, was encountered. Stations 
10057 and 10086 were located at the same geographic position off 
Highland light, and the only apparent change which had taken place 
during the interval of four weeks which separated them was that the 
Staurophora, Stephanomia, and Beroe, which had been prominent im 
the tow early in July were no longer found. Off Massachusetts Bay 
we found a typical Calanus plankton, with Euchaeta norvegica, north- 
ern schizopods, Sagitta elegans, Euthemisto, Limacina balea, Pleuro- 
brachia, Melicertum, Tomopteris helgolandica, Euchaeta, and hosts ol 
