ORDER TUNICATA. — ASCIDEA. 259 



ASCIDEA MANHATTENSTS. 



Description. Oblong-oval, globular ; orifices distant, elevated and surrounded by ten to 

 thirteen verrucose processes ; externally corrugated, often covered with marine sordes, con- 

 cealing the natural color. When held against the light, the intestinal canal may be indis- 

 tinctly traced. The shape varies according as they are crowded together or isolated ; in the 

 latter case, they are oval-orbicular. 



Color. Uniform ashen-grey or brown. 



Diameter, 0"3 - l'O. 



In the young, the orifices are both terminal. The aperturae incamatas attributed by Lin- 

 neus to the rustica, are wanting in this species, and the references to Miiller indicate a very 

 different animal. The ovalis of Lesueur, another allied species, has the tubes plaited. Our 

 species is commonly found in the months of September and October, adhering to stones, 

 dock-logs, and other submerged bodies. I refer to it a small Ascidea, about 0*3 in diameter, 

 adhering to salt grasses. 



(EXTRALIMITAL.) 



A. rustica. (Lam. Vol. 1, p. 584. Gould, Invert. Mass. p. 319.) Rough; varying in size from 

 a pea to that of a musket ball. Color, ferruginous ; the orifices flesh-colored. Northern Coast. 



A. plicata. (Lesueur, Acad. Nat. Sc. Vol. 3, p. 5, pi. 3, fig. b.) Body ovate, sessile: surface sub- 

 glabrous, but with many large inflated folds on the side of the inferior aperture, crossed by smaller 

 folds, and giving the appearance of small imbricated dilatations. Apertures approximate, unequal, 

 terminal. Color, white. Length, 2-0. Ships' bottoms. Philadelphia. 



A. ovalis. (Id. lb. p. 6, pi. 3, fig. a.) Sessile; somewhat smaller than the preceding, and without 

 the inflated folds. Apertures large, distant, placed at the extremity of two short plaited tubes : skin 

 round the aperture thin, and apparently divided into many small obsolete angles. Color, white. 

 Same locality with the preceding. 



A. lobifera. (Id. lb. p. 7.) Body sessile, wrinkled, subglobular. Apertures approximate, unequal, 

 concealed among many irregular fleshy lobes. Color, dull black. Length, 1*5. Florida. 



A. proboscidea. (Id. lb. p. 6, pi. 1, fig. 4, 5.) Smooth ; with an elongated proboscis containing the 

 two tubes. Apertures placed on the summit of the proboscis, and contiguous. Color, white. An 

 Ascidea ? Coast of Georgia. 



The A. intestinalis and microcosmus have also been stated to occur on the Northern Coast. 



