1886.] . Zoology. -385 
ZOOLOGY. 
PHOSPHORESCENCE OF MARINE ANIMALS.— The address in Section 
D, biology, of the British Association, was delivered by Professor 
W. C. McIntosh, M.D., of St. Andrews, who selected for his subject, 
the “Phosphorescence of marine animals.” A phenomenon so 
striking as the emission of light by marine organisms could not’ 
fail to have attracted notice from very early times, both in the case 
of navigators and those who gave their attention in a more syste- 
matic manner to the study of nature. Accordingly, we find that 
the literature of the subject is both varied and extensive—so much 
so, indeed, that it is impossible on the present occasion to give 
more than a very brief outline of its leading features: Though it 
is in the warmer seas of the globe that phosphorescence is 
observed in its most remarkable forms—as, for instance, the sheets 
of white light caused by Noctiluca and the vividly luminous bars 
of Pyrosoma—vet it is a feature which the British zodlogist need 
not leave his native waters to see both in beauty and perfection. 
any luminous animals occur between tide-marks, and even the 
stunted seaweeds near the line of high-water everywhere sparkle 
with a multitude of brilliant points. As a ship or boat passes 
through the calm surface of the sea in summer and autumn, the 
wavelets gleam with phosphorescent points, or are crested with 
Phosphorescent points, or are crested with light; while the 
observer, leaning over the stern, can watch the long trail of 
luminous water behind the ship from the brightly sparkling and 
Seething mass at the screw to the faint glow in the distance. 
On the southern and western shores, again, every stroke of. 
lower and 
interest and beauty. He glanced, in the first instance, at the various 
etazoa, viz., ccelenterates, echinoderms, worms, rotifers, 
ii k 
crustaceans, molluscoids, mollusks and fishes. In foreign seas 
Agassiz describes Mnemiopsis leidyi as “ exceedingly phosphor- 
escent, and when passing through shoals of these Medusa, vary-. 
ing in size from a pin’s head to several inches in length, the whole 
; comes so brilliantly luminous that an oar dipped in the 
as Water up to the handle can plainly be seen on dark nights by the- 
z 
Ihe ci omotive rows ; and so exceedingly sensitive are they that — 
k slightest shock is sufficient to make them plainly visible by - — 
Fae 1e light emitted from the eight phosphorescent ambulacra.” The 
: VOL. XX.—no, Iv. S 
