INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 321 



twelve pairs of scales, but they are rough, and covered with small 

 rounded or hemispherical tubercles ; this is usually dark brown. The 

 third species has sixteen pairs of smooth scales, and belongs to another 

 genus. This is Harmothoi' imbricata ; it varies exceedingly in color, but 

 is usually grayish or brownish, more or less specked, blotched, or striped 

 with blackish ; sometimes there is a black stripe along the middle of 

 the back ; sometimes the general color is dark reddish. These three 

 species of scaly Avorms all have a large proboscis with four i^owerful 

 jaws at the end, and a circle of papillne, as in figs. 40 and 41; they are 

 carnivorous in their habits and rather sluggish in their movements. 

 When disturbed they curl themselves up into a ball. They are very 

 complicated in their appendages, and the spines and seta?, of these ap- 

 pendages are very curious in structure, when examined with a micro- 

 scope. Notwithstanding their numerous sharp spines they are often 

 devoured by fishes, and they frequently also fall victims to their more 

 powerful companions belonging to the Nereis tribe, and are sometimes 

 destroyed even by the apparently inotteusive Nemerteans. Adhering to 

 the under sides of the rocks and stones there are several kinds of tubes 

 constructed by annelids. One of the most common and abundant kinds 

 of these tube-dwelling worms is the Sahellana ruJ[iaris V., (Plate XVII, 

 figs. 88, 88tT.) This worm constructs firm and hard tubes out of fine sand 

 and a cement secreted by special glands. These tubes are bent and 

 twisted in various directions and are generally united together into 

 masses or colonies, sometimes forming aggregations of considerable 

 thickness and perhaps several inches or a foot across. The tubes of this 

 worm are also common on the shells of oysters. Another very curious 

 and beautiful worm, the Scionopsis 'pahnata Y., constructs much larger 

 and coarser tubes out of bits of sea-weeds and shells, sand, small pebbles, 

 and other similar materials; these tubes are long and crooked and 

 attached for their whole length to the under side of rocks. The worm 

 that constructs them has some general resemblance to the AmpMtrUe 

 ornata, but is seldom more than three or four inches long and is usually 

 darker colored, the color being generally reddish brown or dark brown, 

 more or less speckled with white. There are only seventeen fascicles 

 of set?e on each side. The gills are only three in number, viz : an odd 

 median one, much larger than the others, placed just behind the tentacles ; 

 and a pair of smaller ones, but similar in form and just back of the first ; 

 all three gills have a stalk or i)eduncle, and branch toward the end in a 

 palmate or digitate manner, each of the divisions again subdividing. 

 The gills can be retracted beneath a sort of collar which arises just be- 

 hind them; their color is greenish, specked with white. The gills of 

 this worm are very elegant in form, and quite unlike those of any other 

 known species, both in position and form. Therefore it is necessary to 

 establish a new genus for this species. It has been found from Vineyard 

 Sound to New Jersey ; both among eel-grass in shallow water, and under 

 stones. The Nicolea simplex is a related species, with similar habits. 

 H. Mis. 61 21 



