14(34 CRUSTACEA. 



north, 108° 11' east, on January 24, it was 67°; in 12° 16' north, 

 109° 28' east, it was 7412° F. The very low Macao temperature is 

 that of the surface of the Bay itself, due to the cold of the land, and 

 not probably, as the other observations show, of the sea outside. 



The line, before passing south, bends northward to the southeast 

 shore of Niphon, which is far warmer than the southeast coast, along 

 Kiusiu. In the Report of the Morrisons' visit to Jeddo (Chinese 

 Repository for 1837), a coral bottom is spoken of, as having been 

 encountered in the harbour of Jeddo. According to Siebold (Crust. 

 Faun. Japon., p. ix.), the mean winter temperature (air) of Jeddo is 

 57° F., while that of Nagasaki, although farther south, is 44° F. 



Isocryme of 62° F.— On January 8, 1827, Beechey found in 29° 42' 

 north, 126° 37' west, the temperature 62-75° F.; while on the pre- 

 ceding day, 32° 42' north, 125° 43' west, the sea-temperature was 

 60-5° F. Again, on December 11, in 29° north, 120° west, the tem- 

 perature was 62 -58° F. 



Isocryme of 56° F. — At Monterey, on January 1 to 5, the sea-tem- 

 perature according to Beechey was 56°; but the mean temperature of 

 the sea for November 1 to 17, was 54-91°. In the Yellow Sea, the 

 January temperature is 50° to 56° F., and the line of 56° begins south 

 of Chusan. 



Isocryme of 50° F. — At San Francisco, from November 18 to De- 

 cember 5, 1826, Beechey found the mean sea-temperature to be 51-14° 

 F., and off Monterey, in longitude 123° west, the temperature was 

 50-75° F., on December 6. But in December of 1826, the mean sea- 

 temperature at San Francisco was 54*78° F.; and for November, 

 60-16° F. The line of 50° F. (mean of the coldest thirty consecutive 

 days), probably leaves the coast at Cape Mendocino. 



Isocrymes of ii° and 35° F. — Captain Wilkes found the temperature 

 off the mouth of the Columbia River, through ten degrees of longitude, 

 48° to 49° F., during the last of April, 1841. The isocryme of 44° 

 would probably reach the coast not far north of this place. The tem- 

 perature on October 21, in the same latitude, but farther west, 147° 

 west, was 52-08° F. On October 16, in 50° north, 169° west, the 

 temperature was 44 -91° F. According to some oceanic temperatures 

 for the North Pacific, obtained from Lieutenant Maury, the sea-tempe- 

 rature off northern Niphon, in 41° north and 142&° east, was 44° F., in 

 March, showing the influence of the cold Polar current ; and in 4^° 

 north, and 149i° east, it was 43° F. The line of 44° hence bends 

 southward as far as latitude 40° north, on the Japan coast. 



