The frisk Naturalist. 
January, 
and travelled with an even, gliding motion. By the 5th 
of May all of the young worms had left their capsules, 
though a majority of them still remained within the general 
mucus envelope. Here they crawled about restlessly, 
gathering into writhing knots or wandering about singly 
on exploring expeditions, until finally a few days later they 
had all achieved their freedom, and the general envelope 
was left empty save for a few aborted eggs and a curious 
tangle of deflated capsules. The young worms were elon- 
gated, elliptical in form, the length about six times the 
breadth. The general colour was white, the anterior third 
of the body much lighter than the posterior two-thirds 
which were marked by longitudinal bands of pale tawny. 
Between these bands and occupying the central region of 
the body the convoluted proboscis was clearly visible. The 
head bore two very distinct and compact eye-spots, red- 
brown in colour and placed transversely and symmetrically, 
that is to say, each separated from the adjacent head- 
margin by an equal space. The whole body was clad with 
cilia in active motion, those along the head -margins or 
cephalic slits being the most conspicuous. 
The eggs had been hatched out in a circular glass petrie 
dish, 2|- inches in diameter by i| inch in depth, fresh sea 
water being supplied from time to time, and about ten days 
after hatching I noticed that the young worms, about 
fifty-five in number, showed a tendency to seek one side of 
the dish. The side preferred happened to be somewhat 
better illuminated than the others, and this action of 
the worms suggesting positive phototropism, I was induced 
to make some test experiments with very simple apparatus. 
The first experiment was made by lamplight on the 17th 
May. The dish, with the worms evenly spread over the 
bottom, was covered with a cardboard box having cut in 
one side an opening one-third inch in diameter. This 
opening, the only one by which light could find access to 
the dish, was placed close up to the side of the dish and 
turned towards a small lighted lamp distant tw^o feet. 
On removing the box after the lapse of fifteen minutes all 
the worms were found congregated in a dense mass on the 
wall of the dish directly opposite to the opening. A few 
