346 W. G. Van Name — Bermuda Ascidians. 



The mantle of the thorax is pure white, not pigmented, while the 

 stomach and more or less of the intestine is yellow or orange. This 

 color fades out in preserved specimens, becoming yellowish or flesh 

 color. In specimens which are in a degenerate condition, the test 

 often becomes infested with parasitic alga^, giving it a dirty and 

 greenish appearance. 



Some specimens preserved in alcohol have the zofeids very dark 

 colored, brownish or blackish. I think this may be due to the action 

 of the alcohol or of something contained in it. I have not seen 

 fresh specimens in which they are so colored. 



The zooids are much smaller than in any of the above species. 

 The longitudinal muscles of the mantle are strong and form distinct 

 bands. In consequence of this development of these muscles the 

 zooids are nearly always found in a condition of violent contraction. 

 This is true of all the species of this genus, but particularly of this 

 one, and most of the zooids in preserved specimens are generally 

 contracted into a shapeless condition. 



There are four rows of stigmata, but a rather small number in 

 each row. Neither are the tentacles very numerous, but they are of 

 two or three different sizes, the largest ones inserted farther back 

 than the smaller ones. In some colonies seven lobes to the branchial 

 aperture is the rule, in others six. The atrial aperture always has 

 six as far as I have observed. There are fewer testes than in any of 

 the larger species of this genus described above. Six appears to be 

 a common number, but in some colonies it is often considerably 

 exceeded. 



Specimens of this species collected in April and May are full of 

 large eggs and embryos in all stages. Four or five large embryos, 

 together at least equalling in bulk the individual which has pro- 

 duced them, ma} r sometimes be found under the mantle of one zooid. 

 Those of most advanced development are nearest the atrial aperture, 

 the others further back, according to their stage of growth. 



This species is abundant and may be found on the under side of 

 stones at every suitable place along the shore, and on corals, etc., on 

 the reefs. It is one of the two or three commonest ascidians at 

 Bermuda. 



Getms Cystodytes von Drascne, 1883. 



Differs from Distoma in that the abdomen of each zooid is 

 surrounded by a capsule of calcareous spicules lying in the test. 

 These spicules have the form of circular disks, thin at the edges and 



