* 

 264 TIDAL IRREGULAEITIES. 



identical in some cases ; in others closely allied to 

 known species from Japan, Australia, and the 

 shores of our own island. 



The tidal irregularities of this coast are per- 

 fectly inexplicable. In May, June, and July, 

 during the twenty-four hours, there is but one 

 high and one low water. At the change and fall 

 of the moon, high-tide happens near midnight, 

 and varies but little as to time during these 

 three months. In August, September, and Octo- 

 ber there are two high and two low tides in the 

 twenty-four hours. Then in the winter months 

 (November, December, and January) the regular 

 twelve-hour tides recur; but high water is at 

 twelve o'clock in the day, instead of twelve 

 at night. The spring-tides range from ten to 

 twelve feet, the neaps from five to eight. 



The temperature of the sea, taken during the 

 summer months near the surface, ranges from 

 52 to 56 F. The sea-water seldom, I may say 

 never, looks clear, but always presents a turbid 

 muddy appearance, as if a large quantity of sand 

 was mixed with it. This may in some measure 

 be accounted for by assuming that strong under- 

 currents flow from north to south, and sweeping 

 past the island, and being (from their low speci- 

 fic gravity) close to the bottom, stir up sand and 



