{323] INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 29 
around to the sides, open upward by a free extremity; they also fre- 
quently occur in sheltered nooks in thetide-pools. The worm, when un- 
disturbed, puts out a beautiful wreath of branchis somewhat resembling 
that of the Serpula, but there is no operculum. The branchiz are always 
beautifully colored, though the colors are quite variable. In one of the 
commonest styles of coloration, the branchiz are surrounded at base 
with reddish brown; above this with a ring of white; next by a band 
of reddish brown ; then for the terminal half the color is yellowish gray, 
with indistinct blotches of brown; onthe outer sides of the branchiz 
there are one to three dark red eyes. There are ten or more branchie 
in each half of the wreath, and they are longer on one side than on the 
other. 
Another related species, the Sabella microphthalma V., also occasionally 
occurs in the pools and on the under sides of stones, constructing tubes 
very much like those of the last species. This is a mueh shorter and 
stouter worm, with the branchial wreath relatively much larger and 
nearly half as long as the body. The branchiz are pale yellowish, 
greenish, or flesh-color, with numerous transverse bands of darker green 
extending to the pinne; on the outer side of the branchize there are 
numerous minute eye-like spots of dark brown, arranged in two rows on 
each. The body is usually dull olive-green. The Fabricia Leidyi V., is 
another member of this group of worms, but is of very minute size. It 
constructs delicate, flexible tubes, free toward the end, which usually 
stands upright. Its tubes may be found in the pools.and on the under 
side of stones. The worm itself is very small, slender, and when un- 
disturbed protrudes a wreath, composed of six branchiz, to a considera- 
ble distance above the mouth of the tube. The branchiz have five 
to seven pinne on each side, the lowest much the longest, so that when 
expanded they all reach nearly to one level. At the base of the bran- 
chie there are two pulsating vesicles, alternating in their beats; and 
just back of these there are two minute brown eye-specks; two similar 
eyes exist at the posterior end. Eleven segments of the body bear fas- 
cicles of setze. Color yellowish white, the blood-vessels red. 
Two or more species of the minute but beautiful worms belonging to 
the genus Spirorbis are found attached to the fronds of sea-weeds, to 
shells, stones, &c., especially in the pools. These are related to the 
Serpula, and like it form solid calcareous tubes, but these are always 
coiled up in a close spiral, and the coil is attached by one side. The 
little worms put out an elegant wreath of branchi, and are furnished 
with an operculum. Another very interesting and beautifully colored 
worm, sometimes found under and among the stones, where there is 
mud, is the Cistenides Gouldiit V., (Plate XVII, figs. 87, 87a.) This 
constructs very remarkable, conical, free tubes, of grains of sand ar- 
ranged in a single layer, like miniature masonry, and bound together by 
a water-proof cement. This worm belongs more properly to the muddy 
and sandy shores and will be mentioned again. 
