[621] INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 327 



branchiae are lemon-yellow or orange-yellow, without bands, but usually 

 with a reddish central line; the operculum is usually yellow ; collar and 

 base of branchia3 bright yellow ; body light yellow. 

 Found with the preceding, and often in the same cluster of tubes. 



YERMILIA (?), species undetermined, (p. 416.) 



The species thus indicated forms slender, more or less crooked, angu 

 lar tubes, with two distinct cariuations on the upper surface ; they are 

 about half an inch long, attached firmly by one side along their whole 

 length. The branchiae form a wreath, with about six on each side ; pinnae 

 long and slender ; two or more of the branchiae bear pink, sack-like 

 appendages. The branchiae are reddish brown, annulated with narrow 

 bands of white. 



Diameter of tubes, about 1.25 mm ; of expanded branchiae, 4 mm . The 

 specimens have been lost, and no observations were recorded concerning 

 the operculum, so that the genus is still uncertain. 



Long Island Sound, off New Haven, in 4 to 6 fathoms, on shells. . 



SPIRORBIS BOREALIS Daudin (?). 



Rec. des m6m. de mollusques, 1800. Serpala spirorbis Liune, System a Naturae , 

 ed. xii, p. 1265. (?) Spirorbis spirillum Gould, luvertebrata of Mass., ed. i, p. 8 ? 

 1841; A. Agassiz, Annals Lyceum Nat. History of New York, vol. viii, p. 

 318, Plate 7, figs. 20-25 (embryology), 1866 (not of Linne&quot; and other European 

 writers). 



New Haven to Cape Cod, the Bay of Fundy, and northward; abun 

 dant on Fucus, Chondrus crispus, and other algae, at low- water mark. 



Whether this, our most common species, be identical with the Euro 

 pean species known by this name is still uncertain. 



The animals of the various species of Spirorbis are still very imper 

 fectly known, and many species have been described from the tubes 

 alone. Accurate descriptions or figures of the animals are necessary 

 before the species can be determined satisfactorily. 



This species has nine branchiae, five on one side and four on the other 

 with the operculum. The branchiae are large and broad with long pinnae, 

 the basal ones shorter, the distal ones increasing in length to near the 

 end, so that each branchial plume is somewhat obovate in outline ; the 

 tips are naked only for a short distance. The branchial wreath, in full 

 expansion, is about as broad as the entire shell. The operculum is oblique 

 and one-sided, and supported on a long clavate pedicel, which is trans 

 versely wrinkled, and expands gradually into the operculum at the end, 

 the enlargement being chiefly on one side ; the outer surface is roughly 

 granulous and usually covered with adhering dirt. The collar is broad, 

 and has three fascicles of setae on each side. The branchiae are pale 

 greenish white, centered with brighter green, due to the circulating fluid. 



This is the species mentioned in the early part of this report (p. 332) 

 under the name of S. spirillum. The true spirillum of Linne as a trans 

 lucent tube, and is found in deeper water, on hydroids, &c. 



