316 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
apt to be overlooked unless unusual attention is given to hunting for 
them. 
The ‘cut’ mentioned above (B. B. S. station 1408) deserves 
special mention. This is an artificial channel made in the limestone 
rock, three feet or so wide, and extending in a straight line through 
a narrow neck of land between Harrington Sound and the Flatts 
Inlet. The tides rush through this ‘ cut,’ alternately in and out, with 
great swiftness, and collecting is feasible only at or near the ebb, 
when the water is barely two to three feet deep. Direct sunlight is 
almost entirely excluded, owing to the high vertical sides of the 
canal and the overhanging vegetation. Here in the half-light such 
animals as sponges, especially the brightly colored, encrusting forms, 
bryozoans, and hydroids grow in the greatest abundance. All but 
two of the Pycnogonida collected this year came from among the 
hydroids at this place, where they are associated with Caprella, 
which occurs in large numbers. 
The conditions found here suggest an interesting problem kt the 
etiology of these animals. With the tide almost constantly sweep¬ 
ing through, one way or the other, how is it that the pycnogonids 
remain abundant; why is it that they are not all swept away ? The 
adults, it is true, cling tenaciously by their feet, which can clasp a 
small hydroid stem or similar object very efficiently when the claw 
is bent back against the sole. This is especially the case when the 
heel, with its distally projecting strong spines, is developed. But 
the danger comes to the eggs and the larvae. In the case of 
sponges and similar organisms which produce large quantities of 
young, these, although set free into the water, are so abundant that 
the stream passing through is sure to contain many of them; some 
of these probably become lodged in the ‘ cut ’ and attach them¬ 
selves there, so that the place remains stocked. But pycnogonids 
produce relatively few eggs. If these were set free, the chances 
are that they would be carried away and very few, if any, would 
find lodgment in the ‘ cut ’; but as a matter of fact the eggs are taken 
directly from the female by the male ( cf . Cole, : 01 , p. 204) and are 
carried by him until they are hatched. The newly hatched larva of 
Ammothea and related forms bears a large pair of chelae on the 
enormously developed chelifori, by which it is enabled to cling to 
the parent, or to hydroids &nd similar objects. The other append¬ 
ages at this time are of no use in this connection. After the meta- 
