W. G. Van Name — Bermuda Aseidians. 347 



thicker at a point near the center, and slightly concave on the side 

 toward the zooid. The capsule is formed by a varying number of 

 such disks placed overlapping each other, sometimes several deep. 



The zooids are shorter than those of Distoma, and appear to have 

 no vascular appendages. If this be the case, the method of budding 

 must be somewhat modified from that of Distoma. 



Cystodytes draschii Herdman. 



Cystodytes draschii Herdman, Report Voy. Challenger, pt. xxxviii, p. 137. 

 Plate XLIX. Figure 17. Plate LV11I. Figures 99 to 101 inclusive. 



The type of this species, described in the above work, was 

 obtained in 400 fathoms off Barra Grande, Brazil, but Bermuda 

 specimens from shallow water agree almost perfectly with Herd- 

 man's description and figures. 



It forms flat incrusting colonies, about 5 mm thick, and reaching 60 

 or 80 min across. The surface is smooth and the consistenc}' of the 

 test moderately firm. The colonies are usually quite opaque. The 

 color is a dee]), uniform, brownish gray. When the colony is cut 

 the white calcareous capsules surrounding the posterior ends of the 

 zooids are very conspicuous. 



Under the microscope the test is shown to contain enormous 

 numbers of bladder cells, so closely packed in most places that their 

 outline becomes polygonal, and the amount of test substance is 

 actually small. 



A spicule of ordinary size measures from 0.1 to 0.3'" m in diameter 

 and about 0.03 mm in thickness at the thickest point, but somewhat 

 larger ones and of course many smaller ones occur. They resemble 

 the larger kind of spicules of V. vlolaeeus shown in fig. 14. 



The zooids are pale yellow in color when removed from the cap- 

 sule, which is not readily done without tearing them unless the 

 capsule is dissolved away. They are distinct^ divided into thorax 

 and abdomen, but by a very short peduncle, if indeed there can be 

 said to be any. In life, however, they must be capable of some 

 extension, and their usual contracted condition is due to the great 

 strength of the longitudinal mantle muscles. These form many dis- 

 tinct bands on the sides of the thorax, but in the region of the 

 peduncle these separate bands run together and unite into a single 

 broad, thick band on each side. On the abdomen, the muscles spread 

 out again. The object of these strong bands is no doubt to retract 

 the thorax and bring it more or less completely within the protection 



