and Shells of Massachusetts Bay. 73 
some of its members, who have leisure, will also find 
opportunity to investigate it fully. 
I have a suspicion that the cirri in question assist in 
secreting the viscid substance, which is emitted in such 
quantities that the animal is sometimes completely en- 
veloped in it, as the transparent fluid contained in their 
external tunic or sheath (alluded to in the description 
of E. salmondcea), was found to be of a similar nature. 
Nothing was ascertained in relation to their food, but 
from the fecal matter being always semifluid and of a 
blackish or greenish color, it may be presumed that it is 
chiefly vegetable. Their ova are deposited in irregular, 
gelatinous envelopes upon the sticks, weeds, &c., in the 
vicinity of their habitat—the masses containing from one 
hundred ova each, to a thousand or more. The ova 
themselves are oblong, detached, and of a grayish white, 
the enveloping matter being perfectly transparent. 
It is rather a singular fact, that although both the 
Eolides and 'T'ritonie were so abundant last year, I have 
been unable to discover a single individual of either 
genus this season. Might they not have been acciden- 
tally introduced to our waters upon the bottoms of ves- 
sels, while in the ova? That foreign mollusca may be 
so` introduced, we have evidence in the case of the 
United States ship Erie, which arrived in our port, the 
past autumn, from the coast of Brazil; bringing on her 
bottom great numbers of a variety of Myrtus achatinus, 
Lk. and a small species of Purpura, both of which I 
met with, some time after her repairs at the Navy Yard 
in Charlestown, adhering at low water to the piles out- 
side the dry dock at that place. It is not impossible 
that the ova of the animals alluded to, may have been 
brought hither in a similar way. If they were naturally 
