[415] INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 121 



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 moliusks, 

 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 &quot;banks 77 and &quot;fishing-grounds&quot; 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 dredgiug-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, Homarus Americanus, (p. 395,) the common shrimp, Cran- 

 gon vulgar is, (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, Eupagurus polllcaris, (p. 313,) the 

 smaller hermit-crab, E. longicarpus (p. 313,) the Heteromysis formosa, 

 (p. 396,) My sis Americana, (p. 396,) Unicola irrorata, (p. 340, Plate IV 

 fig. 19,) Amphithoe maculata, (p. 315, Plate IV. fig. 16,) Corophium cyl- 

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

 Autonoe, w T hich lives in the crevices among the lobes of the sandy 

 ascidians (Amarcedum pellucidum) in large numbers. The barnacle, 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, Libinia. 



Clinging* to and creeping over the hydroids and ascidians a singular 

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

 Phoxichilidium maxillare, (Plate VII, fig. 35.) It is most frequently 

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



The larvae of a fly, Chironomus lialopliilus, was dredged in five 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 asoidimis, found equally on both kinds of 



