336 W. G. Van Name — Bermuda Ascidians. 



luosing vessels with enlarged ends, which occur in the lower parts 

 of the colonies. These vessels arise from the posterior ends of the 

 zooids. 



The largest zooids measure, in the preserved condition, about 

 22'"™, or slightly moi'e, in length when removed from the test. In 

 formalin tiiey are of a pale flesh-color. The white contents of the 

 intestine show plainly from the outside. 



The mantle is provided with a varying number of rather narrow 

 longitudinal muscle-bands. Beneath these bands there are still nar- 

 rower transverse bands of different sizes, which are spaced rather 

 far apart, so as to form with the longitudinal muscles square or 

 oblong meshes often of considerable regularity. (Fig. 5.) On the 

 abdomen, the musculature becomes weak and inconspicuous. The 

 siphons have delicate longitudinal and sphincter muscles. The 

 apertures are not lobed, but in contraction their edges become 

 thrown into folds which may easily be mistaken for lobes. 



There are fifteen or more rows of stigmata in the branchial sac, 

 each with a great number of short but narrow and closely placed 

 stigmata. The transverse vessels are muscular and have very wide 

 membranes attached along their inner sides. These membranes unite 

 with each other and with the rather long tapering dorsal languets at 

 the dorsal lamina. The dorsal lamina itself is rather broad, and has 

 a thick muscle-band along each side. 



There are about a dozen tentacles placed rather far apart and 

 forming a single circle in which large and small ones alternate, but 

 in addition to these there are numerous much smaller ones inserted 

 farther forward and apparently forming more than one circle. In 

 this it resembles the genus Distoma. There are no atrial tentacles. 



The stomach is smooth-walled and elongated. It is provided with 

 a single internal ridge running longitudinally, and a similar ridge 

 may be traced along a large part of the intestine. 



The reproductive glands are poorly developed in the specimens in 

 the collection. The ovary is elongated and situated in the loop of 

 the intestine, and in most cases contains numerous small eggs, but 

 no large eggs or embryos were found. There is a well developed 

 oviduct. 



" Harrington Sound and Castle Harbor, just below low-tide, 

 usually attached to gorgonioe or bryozoa " (Verrill). One or two 

 large colonies, and many small ones, were collected in 1898 ; but in 

 1901 only a few small ones were found. It appears to grow chiefly 

 on the gorgonian Muricea muricata. 



