INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 415 



the shells and pebbles or between the ascidians, &c., like many of the 

 larger annelids, some of the crabs, and other Crustacea, &c. ; they may 

 be species that live among or attached to the hydroids, bryozoa, ascid- 

 ians, and algae which grow upon the shells and pebbles ; such are many 

 of the small Crustacea, some annelids, many small gastropod shells, and 

 most of the more delicate bryozoa and hydroids ; or they may be larger 

 kinds that creep or swim about over the bottom, in search of food, such 

 as the lobster, the larger crabs, hermit-crabs, large gastropod mollusks, 

 star-fishes, sea-urchins, holothurians, &c. Owing to the great abundance 

 of animal life on bottoms of this character they are the favorite feeding - 

 grounds of many kinds of fishes, such as the tautog, scup, black 

 bass, haddock, and cod, together with many others that are less valua- 

 ble. Most of the "banks" and "fishiug-grounds" resorted to by the 

 line fishermen have either gravelly and shelly or else rocky bottoms, 

 and those banks most frequented by fishes are almost always found to 

 be rich dredging-grounds. The gravelly banks in this region are, in 

 winter and spring, fishing-grounds for cod and haddock, but these fishes 

 retreat to colder waters in the summer. 



Among the Crustacea the most abundant and important species are 

 the lobster, Somariis Amerieanus, (p. 395,) the common shrimp, Cran- 

 gon vulgaris, (p. 339, Plate III, fig. 10,) the common rock-crab. Cancer 

 irroratus, (p. 312,) Panopeus Sayi, (p. 312,) P. depressus, (p. 312, Plate 

 I, fig. 3,) the larger hermit-crab, JEupagurus polUcaris, (p. 313,) the 

 smaller hermit-crab, U, longlcarpus (p. 313,) the Heteromysls formosa, 

 (p. 396,) My sis Americana, (p. 396,) Unicola irrorata, (p. 310, Plate lY 

 fig. 19,) Ampliitlioe maculata, (p. 315, Plate IV. fig. 16,) Coropliium cyl- 

 indricum, (p. 370,) which lives among the hydroids, and a species of 

 Autonoe\ which lives in the crevices among the lobes of the sandy 

 ascidians {Amaroecium pellucidum) in large numbers. The ba rnacle, Bal- 

 anus crenatus, (p. 396,) is very abundant. 



One of the most interesting of the Crustacea met with was the Het- 

 erocrypta granulata, which occurred off Falmouth and near Suconesset 

 light-ship. This is one of the triangular crabs in which the carapax is 

 smooth ; the chelipeds are long and triangular. It is a southern 

 species, occurring on the Florida coast, and is new to our fauna. 



Another triangular crab, the Pelia mutica, also occurs on these bot- 

 toms, but this has a rough carapax, and resembles a small specimen of 

 the common spider-crabs, Lihinia. 



Cliuging to and creeping over the hydroids and ascidians a singular 

 long-legged Pycnogonid is often met with on shelly bottoms. This is the 

 PhoxicMlidium onaxillare, (Plate YII, fig. 35.) It is most frequently 

 deep purple in color, but gray and brown specimens are often met with. 



The larv?e of a fly, Chironomus lialopMluSj v^SiS diedged in Hyg fathoms. 



The Annelids are quite numerous, and the majority of them are the 

 same as those found on the rocky bottoms, for the same species inhabit 

 the interstices of the massive ascidians, found equally on both kinds of 



