[379] INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 85 
Stantly shaded, very few algie, and those only of the smallest and sim- 
plest kinds, such as Ocillatoriw and Diatoms, are to be found. But in 
these shaded situations many animals, such as Tubularians and other 
Hydroids, some Ascidians, Bryozoa, &c., delight to dwell. Many of 
these adherent animals also live in abundance on the outermost piles of 
the wharves, at or just below low-water mark, where they are more or 
less exposed to the sunlight. 
The animals that are found among or attached to the seaweeds 
growing on the piles are, for the most part, identical with those that 
are to be found in similar situations among the alge on rocks and in 
rocky tide-pools. 
Among those that are nearly or quite peculiar to submerged wood-work 
are several species of ‘ ship-worms,” (Zeredo of several species, and the 
Aylotrya fimbriata,) which are bivalve mollusks; the wood-eating Lim- 
noria; several species of barnacles, which belong to the Crustacea ; 
some of the tubularians, and other hydroids, &e. 
Of the salt-water Insects two species have been observed on the piles 
of wharves. One of these is a small, slender, green larva, with a dark, 
firm head, and sharp jaws. It is the larva of a small, two-winged fly, 
probably identical with the Chironomus oceanicus of Packard. 
On the piles of a wharf at Menemsha, Dr. Edward Palmer found, in 
October, a very interesting insect-larva. It lived in a stout tube com- 
posed of grains of sand firmly cemented together, and attached by its 
whole length to the piles; the single specimen is broken at both ends. 
The tube is flattened, and consists of a central, subcylindrical, tapering 
portion, or proper tube, which is covered on all sides with a single layer 
of small grains of sand, neatly arranged; along each side of this, and 
partly covering its upper surface, and to fill the angle between it and 
the surface to which it was attached, larger grains of sand are cemented. 
The preserved portion of the tube is about three-quarters of an inch 
long and nearly one-quarter wide, at the larger end, but not more than 
half as wide at the small end. The larva is about a third of an inch 
long, rather stout, and has a pair of long, sharp, curved jaws, and three 
pairs of rather long, hairy legs. It belongs to the Phryganide, among 
the Neuroptera, and somewhat resembles some of the well-known larvee 
of the caddis-flies, common in fresh water, which make tubes or cases 
of various kinds. Dr. Hagen, who has examined this specimen, refers 
it to the genus Molanna, of which three North American species are 
known, but only in the adult state. All the larvie of this genus, known 
in Europe, live in fresh water, and no other species of the Phryganidie 
has been observed in sea-water, although some live in water that is 
slightly brackish. 
Of Crustacea the most important species is the Limnoria lignorum, 
(p. 370, Plate VI, fig. 25.) This little creature is grayish in color, and 
covered with minute hairs. It has the nabit of eating burrows for 
itself into solid wood to the depth of about half an inch. These bur- 
