INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 405 



plants. The stein is very delicate, filiform, jointed, and at intervals 

 gives off two very slender, opposite branches, which diverge at right 

 angles, and in their tnrn branch at intervals in the same way. The 

 cells are small and oval or elliptical, mostly arranged in clusters at or 

 near the branchings of the stems, but some are often scattered on 

 the branches ; they are attached by a narrow base. It occurs both at 

 low-water in pools and in shallow water among rocks. The V. armata 

 is also a creeping species, but the cells are terminated by four conical 

 prominences, each of which bears a slender spine when perfect. This 

 also occurs both between tides and in shallow water, on hydroids and 

 bryozoa. 



With these species of Vcsicularia, and often attached to them and 

 creeping over them, as w^ell as on other kinds of bryozoa, hydroids 

 and algiie, a very curious little species often occurs, in which the cells 

 are small, campanulate, and raised on slender pedicels, which rise 

 from slender, white, creeping stems. This is the Pedicellina Americana. 

 The zooids, when expanded, display a wreath of twelve or more tenta- 

 cles ; in contraction and when young they are often clavate. 



The uJ^tea anguinea has not been recorded as from our coast, but is very 

 common on rocky and shelly bottoms, creeping over various hydroids, 

 algfe, ascidians, broyozoa, &c. ; it also frequently occurs on floating eel- 

 grass and algai, in com^mny with many hydroids. It consists of delicate, 

 white, creeping, calcareous stolons, from which arise elongated, slen- 

 der, clavate, white, rigid, erect cells, with the aperture at the end; the 

 narrower, pedicel-like portion of the cell is surrounded by fine, circu- 

 lar, punctate stria?. . 



The Eucrat&clielata is also a slender, creeping species, and has some- 

 what similar habits, but is much less common, and has been met with 

 only in the deeper parts of Vineyard Sound on ascidians and hydroids. 

 In this species each cell arises from the back of the preceding one, near 

 the end, and bends upward and forw^ard obliquely, the cell expanding 

 from a narrow, pedicel-like, basal portion to a more or less oval upper 

 part, with the aperture oblique and subterminal. This, also, is a new 

 addition to the fauna of our coast, although, like the last, long well 

 known on the coast of Europe. 



The Diastopora patina grows attached to alga? and eel-grass; it forms 

 little circular disks, with tubular cells arising from the upper surface, 

 those in the middle being longest. 



The Tubulipora Jiahellaris frequently occurs attached to various kinds 

 of slender-branched algae, such as Ahnfeltia plicata, &c. It forms small, 

 blunt-lobed, coral -like masses, composed of long, crooked, tubular cells, 

 united by a porous mass at base. Toward the borders of the lobes the 

 cells are crowded and polygonal. In the central j)arts they are more 

 cylindrical and form groups or radiating rows. Associated with the 

 preceding on the algte, Crisia ehurnea, (p. 311 ;) Mollia hyalina, (Plate 

 XXXIV, fig. 264;) Cellepora ramulosa, (p. 312;) and other species oc- 



