MORTALITY OF FISHES, WEST COAST OF FLORIDA. 15 



100 parts of the mud dried yielding by analysis : 



Organic matter 10. 50 



Chloride of sodium, alkaline sulphates, etc G. 43 



Salts of lime 8. 75 



Alumina of [and?] oxide of iron [sic] 16.00 



Siliceous matter G3. 25 



Loss . 07 



* * * In the course of a few days I observed the water of the bay under 

 four different aspects. 



First. Ochre-brown, with somewhat of a reddish tinge, and opaque. This, 

 when examined under the microscope, showed animalculae of a spheroid or 

 circular form and of like color to the water. In 12 hours after it was — 



Second. Of a dark green, and still thick aspect, in which, by the microscope, 

 was visible another class of animalculje of an hourglass form, round and broad 

 at each end, but contracted at the center. Although there was but one drop 

 of the water under the glass, a large number of these jumped about. 



Third. The next morning, or in 14 to 16.hours afterwards, the water was a 

 muddyish white. This time the smell in the harbor was most pimgently nause- 

 ating. It is considered the true " painter " when white paint becomes black, 

 and headaches are general, with everybody under its influence. No animalculfe 

 were visible through the microscope in this state of affairs from the second to 

 the third condition. I may add that in the intervening period we had a shock 

 of earthquake at about 5 o'clock in the morning, and during the occurrence of 

 which it may be conjectured submarine volcanic action destroyed all animal life 

 of these insects seen two days previously. 



Fourth. This is the ordinary water of Callao Bay. * * * 



From Hutchinson's description it would appear doubtful that this 

 was Peridinium. Darwin's observations (184:6) may help to clear 

 this up : 



On the coast of Chile, a few leagues north of Concepcion, the Beagle one day 

 passed through great bands of muddy water exactly like that of a swollen 

 river ; and again, a degree south of Valparaiso, when 50 miles from land, the 

 same appearance was still more extensive. Some of the water placed in a glass 

 was of a pale reddish tint and. examined under a microscope, was seen to 

 swarm with minute animalculae darting about and often exploding. Their shape 

 is oval and contracted in the middle by a ring of vibrating curved ciliae. It was, 

 however, very difficult to examine them with care, for almost the instant motion 

 ceased, even while crossing the field of vision, their* bodies burst. Sometimes 

 both ends would burst at once, sometimes only one, and a quantity of coarse, 

 brownish granular matter was ejected. The animal an instant before bursting 

 expanded to half again its natural size, and the explosion took place about 15 

 seconds after the rapid progressive motion had ceased ; in a few cases it was 

 preceded for a short interval by a rotatory movement on the longer axis. About 

 two minutes after any number were isolated in a drop of water they thus 

 perished. 



This may explain the ephemeral nature of the animalculse, and 

 also, since they die in such vast numbers, it is not difficult to con- 

 ceive the consequences of the decay of so much organic matter. 



Carter (1858) ^ows that the various hues of sea water, as described, 

 are due, at least around the Island of Bombay, to one organism. Peri- 

 dinium sanguineuin. In the swimming stage the organism is green 



