MUSEUM OF COMPARATIVE ZOOLOGY. 13 
A transverse section of the Mexican Current from Mariato Point to 
Cocos Island (Plate V.) shows the water to be considerably warmer near 
the mainland than about half-way across to Cocos Island. At the 1,000 
fathom line, the 60° curve is found at a depth of more than 100 fathoms, 
while at Station 3361, at a depth of 1,471 fathoms, nearly the half-way 
point, the 60° curve has risen to a depth of 50 fathoms from the sur- 
face, to sink to 75 fathoms and rise to 25 fathoms again at Station 
3362 at a depth of 1,175 fathoms, and at Station 3364 in 902 fathoms, 
towards Cocos Island, the surface belt becoming again decidedly warmer 
near the island. The curve of 45° temperature corresponds nearly with 
the 300 fathom line, rising near the mainland and falling somewhat 
at Cocos Island. The 40° curve in its turn corresponds practically 
with the 600 fathom line except near the mainland, where there seems 
to have been a colder body of water. 
The bottom temperature of 36°.4 between 1,600 and 1,700 fathoms 
shows a free connection with the oceanic floor, and the temperatures on 
the ridges indicated by the soundings, the one near the mainland (42°), 
the other near Cocos Island (38°), show that they are not parts of an 
oceanic barrier, but are probably short ridges parallel with the mainland 
and the general trend of Cocos Island. 
A temperature section run across the westerly Panamic current in a 
southeasterly direction from Cocos Island (Plate VI. Fig. 1) shows 
remarkably uniform temperature curves of 60°, 45°, and 40°. The 
60° curve, after leaving the shores of Cocos Island, rises to about the 
45 fathom line, the water as we go south gradually becoming warmer, 
and at Station 3375, about 100 miles southwest of Malpelo, the 60° 
curve is down to the 75 fathom line. The 45° curve barely rises above 
the 300 fathom line near Cocos, and at Station 3375 falls somewhat 
below it. The 40° curve is nearly parallel with the 520 fathom line; 
so that going south from Cocos Island the body of water above the 
500 fathom line is considerably warmer than in the section from Cocos 
Island to the mainland. 
gos, divides off Ecuador, one branch, the westerly, extending to the eastward of 
the Galapagos, the other flowing into the Bay of Panama. The westerly branch 
meets the eastern equatorial set, and the eastern branch meets north of the Bay of 
Panama both the easterly equatorial set and the Mexican branch of the California 
Current. There is thus found off the Bay of Panama, from the coast of Costa Rica 
and in a southerly direction, and northerly in the triangle between the Galapagos, 
Point Mala, and Acapulco, a most complicated system of currents and counter 
currents. These currents had a marked effect on the ship’s course, and frequently 
set us one day thirty or forty miles east, the next day as many miles in a westerly 
direction. 
