350 W. G. Van Name — Bermuda Ascidians. 



The Bermuda form has the stomach smooth-walled within and 

 without, though, when highly magnified, the inner surface is finely 

 granular. No pits or folds are present, except such as may be 

 produced by the contraction of the bodjr, the stomach-wall being 

 very thin and delicate. The smooth-walled stomach is, as far as I 

 know, peculiar to this species. 



Some of the specimens have the form of rather flat-topped heads, 

 with more or less abrupt edges, attached by a short peduncle. Such 

 heads are usually 10 or I2 mm across the top and (including the pedun- 

 cle) 12 or 15 mm in height, and they often consist of but a single 

 system. Other colonies (figs. IS and 19) form rather thick but flat- 

 tened incrusting masses several centimeters across, attached by the 

 greater part of the lower surface. Between these and the heads 

 there is every gradation. The incrusting colonies usually contain 

 several systems, and may be produced into one or more lobes, or 

 more or less distinct heads. 



The test is only moderately firm, but the outer layer is somewhat 

 tougher. It is rather opaque, yet the zooids and the vessels may 

 usually be distinguished. The latter occur chiefly in the peduncle 

 and lower parts of the colonies. They seldom branch or anastomose, 

 and their terminal portions are only slightly enlarged. The test 

 may or may not contain groups or masses of bladder-cells. 



No reliance whatever can be placed on the color of the colony as 

 a specific character. Whatever vcmy be the color, it generally 

 becomes darker on the upper surface of the head or colony, espe- 

 cially about the atrial aperture or apertures, and paler on the sides 

 of the colony and on the peduncle, if one is present. Sometimes 

 the upper surface is nearly black, and some white pigment is often 

 present about the orifices. Usually the colonies have a chocolate 

 brown color: this often shades into olive, violet, purple, or rose color 

 in some parts of the colony, or one of these colors may predominate. 

 All these colors turn to a green, blue-green, or yellowish green, or 

 sometimes a deep blue, when the specimen is preserved in formalin. 



Two large colonies obtained in 1901 were deep orange-red, almost 

 vermillion, shading to blackish about the atrial orifices. These col- 

 onies turned brownish in formalin. Among the specimens obtained 

 by Prof. Verrill in 1898 were a few which were almost white, and 

 others of a dull yellowish olive. These were preserved in formalin, 

 with no notes as to their colors in life. 



The zooids are easily removed from the test. They appear to 

 vary much in size, but this is no doubt largely due to a varying 



