182 Charles W. Hargitt 
clusions. In common with many marine larve the trochophore 
of Hydroides when first emerging from the egg is positively pho- 
totropic, and also tends to swim near the surface. This soon 
changes and within about twenty-four hours it has become some- 
what negative in relation to light, and still later becomes abso- 
lutely indifferent to this stimulus. Following up these facts it was 
found from an examination of a large number of colonies along the 
shore line that in many cases the larvz had attached themselves 
under stones, in shaded places, in crevices, etc. On the other 
hand there were found many exceptions to this, especially from 
the deeper waters. For example, a large colony was obtained 
from New Bedford at a depth of two to three fathoms, attached to 
the sides, both inner and outer, of a granite-ware kettle. Had 
there been any definite compelling action of negative phototropism 
one should have found the larger portion of the tubes on the inner, 
because darker, side of the kettle. But the very opposite was the 
case, probably at least 75 per cent being on the outer and vertical 
sides of the vessel. On the assumption that attachment has some 
relation to food getting, or respiration, this is just what should 
have been expected, and this I am convinced is by far the most 
important factor in this phase of behavior. Colonies which settle 
in crevices, or secluded places soon come to show readjustments 
which have undoubtedly a definite relation to the above-mentioned 
ends. To attain these ends there will be, in many cases, just 
the complex and curious serpentine coilings which these tubes 
display. 
The variable places and modes of habitat are of no small sig- 
nificance in relation to the problem of behavior here under dis- 
cussion. In addition to features of this shown in the former 
paper still further facts have come to light. As intimated above 
habitat is extremely variable, and there is little to show that any 
single factor has a determining influence in the matter. While 
rocks, shells, etc., are the more common places of attachment, 
it is chiefly due to the fact that these are more abundant and avail- 
able. They occur, not only on dead shells where they are extremely 
common, but are also found on shells occupied by living snails 
and bivalves. J have taken them on Sycotopus, Fulgur, Littor- 
