38 MCMURRICH. [VoL. III. 
Duchassaing and Michelotti have described it (60-66) from 
Guadeloupe and St. Thomas. , 
In color (Pl. I., Fig. 8) the column is cream-white shading off 
above into a brown, occasionally dark seal-brown. The disc is 
brown, with opaque white patches. The tentacles are greenish 
brown or white, those of each color being arranged in groups, 
so that the surface of the animal has a variegated appearance. 
According to Duchassaing and Michelotti (60) the color of the 
tentacles changes so that in the space of some hours they can 
pass from one color to the other, but I did not observe this 
peculiarity. The gonidia are well marked, being of a canary- 
yellow color, while the stomodzeum is white. 
The base is usually somewhat smaller than the column, and is 
frequently very irregular in shape. It is capable of adhering 
firmly to various objects, but not infrequently I gathered speci- 
mens which did not seem to be attached to any solid body, but 
simply imbedded in the sand. The column is capable of con- 
siderable extension, but in their normal condition most speci- 
mens are more or less contracted, measuring about 1.5-2, occa- 
sionally 5 cm. in height. In an aquarium, however, where there 
was no sand in which the animals might imbed themselves they 
extended much more, one form measuring in such conditions 
13.5 cm.in height. The upper portion of the column is provided 
with verrucz arranged in vertical series, which are, however, in 
many cases very indistinct, being of the same color as the col- 
umn. In some specimens, on the other hand, they stand out 
very prominently, being of a brownish or greenish brown color. 
In structure these verrucz resemble closely those of Az/actinza, 
being characterized by the absence of the large club-shaped 
glandular cells which are elsewhere present in the ectoderm of 
the column. The layer of small pyriform cells, so evident in 
Phymanthus (q. v.), was not clearly distinguishable in sections, 
though there were apparently numerous peculiar cell elements 
in that region of the verrucal epithelium in which the pyriform 
cells occur in Phymanthus. 
An exceedingly well-developed circumscribed endodermal 
sphincter muscle (Pl. III., Fig. 15) is present, notwithstanding 
that the animals do not seem to be able to retract the tentacles ; 
in Polysiphonia tuberosa, in which there is a mesoglceal sphinc- 
ter muscle, R. Hertwig (’82) observed the same absence of a 
