On the Phosphorescent Spots of Poricthys Margaritatus. 33 
a fish possessing such organs lives in shallow water is, therefore, 
of considerable interest. : 
Porichthys is nocturnal in its habits. It probably remains in 
the deeper water of the bay during the daytime, not having been 
caught in the fishermen’s nets in daylight so far as we are 
aware, but is reported to be quite frequently taken at night. 
We have it from hearsay that specimens have been 
owen with hook .and Jineé during the day. In 
March, 1889, we saw the fishermen draw their seine 
after 8 o'clock P. M., when they caught four specimens. 
The fish were not phosphorescent when brought ashore. Two of 
them were taken in a bucket of sea-water to our laboratory, but 
they showed no signs of phosphorescence. One was dissected; 
the spine was cut and the spinal cord irritated; neither these 
methods nor local irritation of the spots caused any phosphores- 
cent gleams. The other specimen was kept alive several days in 
fresh sea-water. It was watched at night when undisturbed and 
when irritated, but there was no phosphorescence in either case. 
The phosphorescent spots must either be continually and in- 
voluntarily phosphorescent or they must emit gleams at the will 
of the fish. Thac the first proposition is not correct we have seen. 
The voluntary gleams would probably be emitted under one of 
the tollowing conditions; 1. During the breeding season; 2. 
On capturing prey; 3. In escaping from enemies. 
The spots are so conspicuous and invariable in outward appear- 
ance at all seasons and in both sexes that it is not probable that 
these organs were developed to attract the other sex. ; 
Under the second condition no individuals have come under 
our observation; the only way in which the phosphorescence 
would be likely to aid in capturing prey would be by the attrac- 
tion of other fishes by a continuous glow (Stolephorus delicatissi- 
mus was found in the stomach of one individual). If this were 
the case the individual watched should have shown this glow as 
it was not fed during confinement. A single flash, or successive 
flashes would more probably scare away fishes than attract them. 
The general distribution of the spots makes it improbable that 
they would serve to enable the fish to see its prey; the water 
above, beneath and on the sides of the fish would be pretty 
evenly illuminated. 
There remains only the last condition suggested, which may, 
perhaps, be discarded with the statement already made, that all 
attempts at irritation failed to give any flashes. It may be stated 
in this connection that the fishermen here have not seen any phos- 
phorescence from these fishes when capturing them. 
What the function of the spots may be we are unable to say. 
Aquarium facilities for making extensive and long-continued ob- 
servations are, at present, wanting. Further observations will be 
made as soon as practicable. 
A description of the spots is not necessary here as their posi- 
