388 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



common Teredo, except that it has long, oar-shaped pallets, with slender 

 stalks ; the blade is flattened on the inside and convex externally, and 

 consists of ten to twelve, or more, funnel-shaped segments which set 

 one into another ; their margins project at the sides, making the edges 

 of the blade appear serrated. This species appears to be indigenous 

 on this coast. It has been found living in a sunken wreck in Long 

 Island Sound, near Isew Haven, and I have also taken it from the oak 

 timbers of a vessel, the Peterhoff, employed in the blockading service, 

 during the late war, on the coast of the Southern States. It grows to a 

 rather large size, often forming holes a foot or more in length and a 

 quarter of an inch in diameter, though usually smaller. The pallets are 

 sometimes half an inch long. 



Among the kinds of bivalve shells that do not bore in wood, there are 

 bat few species that commonly inhabit piles of wharves. The most fre- 

 quent of these is the common muscle, Mytilus edulis, (p. 307, Plate XXXI, 

 fig. 234,) which sometimes adheres in large clusters. The common oyster, 

 Ostrcea Virginiana, (p. 310,) often attaches itself to the piles, but in such 

 situations seldom survives the winter. 



Ascidiaus often occur in large quantities attached to the piles, at and 

 justbelow low- water mark, and also on the under side of floating timber. 

 They often completely cover large surfaces and spread over the barna- 

 cles, hydroids, and algge. which have previously located. They grow 

 very rapidly, attaining their full size during a few weeks in midsummer. 



The most abundant species are usually Molgula ManJiattensis (p. 311, 

 Plate XXXIII, fig. 250) and Cynthia partita, (p. 311, Plate XXXIII, fig. 

 246.) At Wood's Hole, on the piles of the Government wharf, in August 

 and September, thePerophoraviridis V. was exceedingly abundant, creep- 

 ing over and covering up the other ascidians as well as the barnacles, 

 hydroids, and alga?. This is a compound or " social" Ascidian, in which 

 stolon-like tubular processes come out from the basal portion of the first 

 individuals and run in every direction over the surfaces of objects to 

 which they are attached, producing buds at intervals, which rapidly 

 develop into little Ascidians like the old ones, and give out other 

 stolons in their turn ; thus they will very soon cover large surfaces, 

 though each individual Ascidian is quite small. The body is com- 

 pressed, broad oval, or more or less rounded in outline, with a terminal 

 branchial, and lateral anal orifice, both slightly raised on short and 

 broad tubes. The body is attached to the stolons by a short narrow 

 pedicle, and is usually not more than an eighth of an inch high. The 

 color is bright green or yellowish green, and the integument is soft and 

 translucent. 



On the piles of the same wharf, and associated with the last, was 

 another compound Ascidian, Amaroecium constcllatum ; this forms solid 

 gelatinous masses, with a smooth, convex surface, usually less than an 

 inch in diameter and about half an inch high, but often larger. The 

 zooids, or individual animals, are quite small, long, and slender, and en- 



