W. G. VanJVame — Bermuda Ascidiaris. 341 



C. — Flattened and incrusting bnt rather thick. Test firm, color 

 greenish black, entirely opaque. Surface smooth. Zooids rather 

 large, with much black pigment. D. obscuratum. 



D. — More or less completely divided into heads raised on short 

 peduncles (small colonies consisting of a single head). Color some 

 shade of greenish yellow or olive. Upper surface of heads smooth 

 and glistening. Zooids of moderate size, somewhat pigmented, and 

 more or less distinctly visible through the test. D. olivaceum. 



E. — Rounded, attached by most of lower surface. Test very trans- 

 parent, usually colorless, soft and gelatinous. Zooids small with the 

 thorax usually pure white and the intestinal loop orange, conspicu- 

 ously visible through the test. D. elarura. 



Distoma capsulatum, n. sp. 



Plate XLVI. Figure 2. Plate LVIII. Figure 107. 



Forms a small rounded or unsymmetrical colony with an uneven 

 surface, which is often slightly raised over the anterior ends of the 

 zooids. Size of largest colony; I7 mm by ll mm across, and 5 to 7 mm 

 in thickness. 



Test colorless, rather tough and firm, containing many included 

 grains of sand and shell fragments, so that it may become entirely 

 opaque. The zooids lie in the test inclined at various angles, and 

 are often so surrounded by sand grains or shell fragments, that each 

 appears to be inclosed in a tubular calcareous capsule. In some 

 specimens the whole of the colony is so crowded with included 

 material that no such arrangement is noticeable. Some sand gen- 

 erally adheres to the surface of the colony also. The zooids do not 

 appear to be arranged in systems. 



Though all the colonies found were very small, the zooids were 

 large and few in number. When removed from the test they are 

 light yellow or buff with the stomach and part of the intestine 

 orange. They often reach 6 mm or more in length in the preserved 

 specimens, which are of course somewhat contracted. 



The mantle is well provided with longitudinal muscles, which are 

 gathered on the thorax into a rather small number of broad but not 

 very compact or solid bands. These may also be traced some dis- 

 tance back from the thorax, but gradually break up into narrow 

 bands or individual fibers toward the posterior end of the zooids. 

 Beneath these longitudinal muscles on the anterior half of the body 

 there are fairly strong transverse muscles, which are, however, not 



