358 W. G. Van Name — Bertmida Ascidians. 



Didemnum solidum, n. sp. 



Plate LI. Figures 31 and 36. Plate LIX. Figure 119. 



But one specimen of this species was found. It is a very irregu- 

 lar colony, inci'usting a growth of seaweed. In greatest length it 

 measures about 45™'", and reaches 4""" or 5°^™ in thickness in places. 

 It is entirely opaque and of firm, almost brittle consistency, on 

 account of the abundance of spicules, which are very evenly dis- 

 tributed in all jjarts of the colony. The surface is, for the same 

 reason, slightly rough to the touch, and the apertures are conspicu- 

 ous. Bladder-cells are scarce in most points of the colony. 



The color is difficult to describe, being a reddish grey or buff, 

 almost a flesh-color, darker above. It fades in preservation. The 

 spicules are very uniform in size and shape, being about .05'"'" tc 

 Q^mm jj-^ diameter, and have very short and stout, but regular and 

 numerous conical points. 



The zooids are light colored and small, and placed rather far apart. 

 They do not much exceed 1'""" in length in preservation, and are 

 rather slender. There are probably not more than 12 stigmata in a 

 row on each side. 



None of those examined had well-developed reproductive organs. 



The colony was obtained at Coney Island, May 16th, 1901, just 

 below low water mark. 



Dideumum savignii Herdman. 



Didemnum savignii Herdman, Report Voy. Challenger, pt. xxxviii, p. 261. 

 Plate LI. Figures 37 and 35. Plate LIX. Figure 112. 



The colony is incrusting but rather thick, and of rather soft, gela- 

 tinous consistency. The color is a rich brown, dai-ker above, and the 

 surface is smooth and glossy, the apertures inconspicuous and the 

 spicules and zooids invisible from the surface. 



The largest specimen measures about 16""" across, and is between 

 gmm ^^^j 4mm jj-^ greatest thickness. 



The test contains great numbers of bladder cells, especially near 

 the surfaces, where they are so abundant that they assume polygonal 

 forms from mutual pressure. The dark color is due to brown 

 pigment contained in the test cells. These pigment cells are most 

 abundant near the upper surface, where they are irregular in form. 

 In the deeper portions of the colony they are oval and less thickly 

 distributed. 



