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[603] INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 309 
SPIO ROBUSTA Verrill, sp. nov. (p. 345.) : 
Body stout, broadest anteriorly, tapering posteriorly, but little de- 
pressed except anteriorly, very convex beneath, flattened above. Head 
broad, somewhat angular; the median lobe truncated and slightly emar- 
ginate in front; lateral lobes a little shorter, wide, obtuse-in front, 
slightly angulated laterally; a small median, conical elevation on the 
posterior part of the head. Antenne long, rather stout. Branchie 
long, narrow, tapering. Upper ramus of the feet with a small, obtuse 
setigerous lobe, bearing a small fascicle of short sete, considerably 
shorter than the branchiz, even on the anterior segments, and a foli- 
aceous process arising behind the setigerous lobe, broadly rounded on 
its thin outer edge; the upper end free and obtusely pointed; farther 
back the setz are shorter and the foliaceous process smaller and less 
prominent. The lower ramus on the anterior segments has a small, 
prominent, semicircular foliaceous process and a small, dense fascicle of 
short sets, crowded in several transverse rows; on the eighth and sub- 
sequent segments the foliaceous processes become larger and wider, and 
the sete more numerous, crowded, and partly uncinate; still farther 
back the sete are nearly all uncinate, except a very small ventral tuft 
of slender ones, and form long, double, transverse rows, projecting but 
little beyond the surface. Color greenish. 
Length, 50™, or more; breadth, 3™™ to 3.5™™, 
Wood’s Hole and Naushon Island; in sand, at low-water mark. 
POLYDORA CILIATUM Claparéde(?). Plate XIV, fig. 78. (p. 345.) 
A. Agassiz, On the Young Stages of a Few Annelids, in Annals Lyceum Nat. Hist. 
of New York, vol. viii, pp. 323-330, figs. 26-38, 1866 (embryology). 
Naushon [sland and Massachusetts Bay; in muddy sand, at about half- 
tide (A. Agassiz). 
The adults of this species were not found by us. The young were 
frequently taken in the towing-nets. 
A young Polydora, belonging perhaps to a different species, was 
dredged off New Haven, in 4 to 6 fathoms, shelly bottom. It was about 
12™" Jong. The color was pale yellow, with small black spots along 
the sides between the fascicles of sete; a red dorsal vessel; antenne 
white. 
OPHELIA SIMPLEX Leidy. (p. 319.) 
Marine Invert. Fauna of Rhode Island and New Jersey, p. 16, 1855. 
Body short, smooth, iridescent, well rounded above, flat below; 
usually found coiled up, so that the extremities meet, or nearly so, and 
resembling in general form the larvie of certain beetles and flies. Head 
very acute conical; the buccal segment suddenly enlarges; mouth be- 
neath, with thick evertile lips, the lower one generally protruded. as a 
large rounded lobe. Posterior end terminated by about ten unequal, 
round, blunt, fleshy, simple papille, of which the two ventral ones 
