:U4 W. G. Van Name — Bermuda Ascidians. 



In external appearance the colonies resemble those of Cystodytes 

 draschii so closely that they were taken for that species until they 

 were cut open. 



Common cloacal apertures are jj resent. The dark pigment of the 

 test is contained entirely in the numerous test cells. The zooids are 

 pigmented much as described in the case of D. convexum, but the 

 pigment is in this case much more thickly distributed and is of an 

 intense black color, so that the whole thorax appears black. There 

 is also much of the black pigment on the vessels of the branchial 

 sac. 



The zooids average about the same size as those of D. convexum, 

 though they appear to be somewhat less stout, and differ from them 

 but very little in structure. 



They have between 15 and 20 stigmata in a row on each side. 



The tubules of the gland surrounding the intestine do not pursue 

 parallel courses along the intestine as in D. convexum, but resemble 

 rather those of D. capsulatum, though they are not so crowded 

 together (fig. 11). 



The colonies contain some tailed larv». 



Distoma olivaceum, u. sp. 



Plate XLVIII. FioxURe 9. Plate LIX. Figure 113. 



This species is also closely allied to D. convexum, but the form of 

 the colony differs. In this species it consists of a flat-topped more 

 or less distinctly pedunculated head of small size, seldom over 5 to 

 S'""^ across, and, including the peduncle, not much over 10™°^ in 

 height. Manj^ of the heads are very small, but usually a number of 

 them are grouped together in a mass which may cover several square 

 centimeters of the stone or coi'al on Avhich the colonj^ grows, the 

 separate heads being connected by the expanded lower ends of the 

 peduncles. In shape the heads resemble those of Distaplia, but 

 average smaller. Common cloacal apertures are probably present. 

 Occasionally no distinct peduncle can be distinguished, the colony 

 being attached by its lower surface, and in such cases it often 

 becomes wider, though of less height than stated above. 



The color also differs from that of U. convexum and is retained, 

 at least for a considerable time, in specimens preserved in f oi*malin or 

 even in alcohol. It is some shade of olive, or yellowish olive,^ or in 

 a few specimens a very dark olive-green. The test is moderately 

 firm, the upper surface is smooth and glistening; the peduncle, how- 

 ever, is coated with an outside layer or pellicle containing fine sand 



