[597] INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 303 
through a large part of the length, narrowed slightly and gradually 
toward the posterior end, and abruptly narrowed anteriorly close to the 
head, which is very small, short, conical, and acute at the tip. On the 
anterior thirty-two setigerous segments the feet consist of a small upper 
ramus, having a small, tapering dorsal cirrus and a minute setigerous 
lobe, bearing a small fascicle of slender and short sets, and a lower ra- 
mus, separated by a narrow space, and consisting of a small upper 
papilla, and a long transverse row of minute, rounded papillae, which 
surmount a narrow, somewhat elevated, crest-like ridge; the first twelve 
or thirteen segments having shorter rows, so as to leave a broad, naked 
ventral space, but those farther back having rows of papilla that nearly 
meet beneath, and thus entirely covering the sides and ventral surface 
for a short distance; these crest-like ridges bear close rows of minute, 
hooked sete. The branchiz commence on the upper surface of the fifth 
setigerous segment, in the form of elongated papillae, which become 
more elongated and narrow ligulate farther back. Posterior to the 
thirty-second seginent the papilliform crests of the lower ramus disap- 
pear, and the lower ramus consists of an elongated papilliform, and finally 
cirriform, upper process, with a minute setigerous lobe at its base, 
bearing fine inconspicuous sete ; and an elongated membranous basal 
portion, decurrent down on the lateral surface of the segment; the up- 
per ramus is connected atthe base by a membranous web with the lower 
one, and consists of an elongated dorsal cirrus, similar in size and shape 
to the branchia, and a very small setigerous lobe, bearing a small fas- 
cicle of fine sete. The branchie are connected by a slight web-like 
basal ridge with the dorsal cirri. Thus there are three parallel rows of 
cirriform or slender ligulate processes along each side of the back, leav- 
ing a broad, central, naked space all along the back. 
Length up to 60™ or more; breadth, 4™™. 
Savin Rock, burrowing in sand at low-water mark, May, 1872. 
ANTHOSTOMA ROBUSTUM Verrill, sp.nov. Plate XIV, fig.76. (p. 343.) 
Body large, long, stout, thickest and rounded, or but slightly depressed, 
anteriorly ; tapering rapidly to the head; posterior portion very long, 
narrowing gradually to the posterior end, flatter or concave above, well 
rounded below, higher than wide, with three rows of long, erect, ligu- 
late, or narrow lanceolate processes along each side of the back, the four 
inner rows largest; and a pair of foliaceous processes on the sides of 
each segment. Head short, conical, acute. Proboscis large, broad, di- 
vided into about eighteen long, narrow, digitate, and suleated lobes, with 
convoluted margins, broadest at the end, and free for a large part of 
their length, but united at the base bya membranous web; or it might be 
described as divided into a lower, two lateral, and two upper main lobes, 
each of which is again divided into three or four digitations. During 
life these are all continually changing in form and length, and generally 
only a few of the processes are protruded at one time. Branchie com- 
