INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 501 



of auiinrtls, and especially for many burrowing- aunelitls, Crustacea, aud 

 bivalve shells. Bottoms of this character pass by insensible gradations 

 into the true muddy bottoms, so that it is very difficult to make any 

 sharp distinction between them, or between the animals that inhabit 

 them. Several localities at which we dredged were quite intermediate 

 in character, so that it is difficult to decide in which division they should 

 be put. Yet there is a very wide difference between the animals of the 

 pure sandy aud of the soft muddy bottoms. Most of the localities where 

 the bottom was of this mixed or intermediate character, and of very fine 

 material, have been classed with the muddy bottoms, because the ani- 

 mals inhabiting them agree more closely with those of the true muddy 

 bottoms than with those of the genuine sandy ones. But in each case 

 I shall endeavor to give au idea of the fauna of typical localities of 

 pure sand, of true mud, of muddy sand, and of sandy mud, so that the 

 more general lists given under the sandy and muddy bottoms, respect- 

 ively, need not cause confusion. 



The special localities where dredgings were made on sandy bottoms 

 are as follows : line 80, «, IGJ fathoms, siliceous sand ; h, ISi fathoms, 

 siliceous sand ; 81, a, h, IG J fothoms, sand ; 85, a, &, 15i fathoms, sili- 

 ceous sand and gravel; Sd, a, h, 25 fathoms, sand and gravel, with some 

 mud and small stones; ofl Watch Hill, G to 8 fathoms, loose siliceous 

 sand, with some stones. Besides these a few other dredgings were made 

 ou similar bottoms, but not recorded. 



Among the Crustacea that are characteristic of the true sandy bot- 

 toms are Flatyoniclius ocellatus, (p. 388, Plate I, fig. 4,) which is, how- 

 ever, more common in the sounds; Euimgurus Bernhardus, a decidedly 

 northern hermit crab: Cmngon vulgaris, (p. 339, Plate III, fig. 10;) 

 Ptilocheirus piriguis ; Idofea Tiiftsii. Where the bottom is of loose 

 siliceous sand, the common Unciola irrorata (p. 310, Plate IV, fig. 19) 

 frequently occurs, usually associated with but few others, except a 

 species of Anouyx, or some closely allied genus, which seems to live 

 exclusively on such bottoms. This last species is rather stout, pale 

 grayish or yellowish white, usually tinged with purple on the back The 

 posterior portion is more decidedly purple, together with the caudal 

 appendages and some of the last epiniera. This was dredged off Watch 

 Hill. 



Several iuterestiug species occurred on the bottoms of fine comj^act 

 mud and sand, in 20-29 fathoms. Among these were Phoxus Kroyeri, 

 which is a northern species; Siphonoecetes euspidatus Sjiith, an undes- 

 cribed species ; Byhlis serrata S^iith, another very iuterestiug new 

 species; undetermined species o^ AmpeUsca, &c. 



Few Annelids are peculiar to true sandy bottoms. Among those of 

 most interest are Sthenelais picta Y., (p. 318;) Liimbriconereis fraglUs, a 

 northern and European species; Anthostoma acutuniY.; and Scolecolej) is 

 cirrata. The last is a northern species found in the Bay of Fundy and 

 north to the Arctic Ocean, and also on the northern coasts of Europe. 



