72 ASCIDIANS CHAP. 
Perophora, Wiegmann, with a short compact body and intestine 
alongside the branchial sac. Clavelina lepadiformis and Perophora 
lister’ are Common British species found at a few fathoms depth 
off various parts of our coast. Both occur round the south end 
of the Isle of Man. In autumn Clavelina accumulates reserve- 
material in the ectoderm cells of parts of the stolon, which remain 
when the rest of the colony dies away, and then form new buds 
in spring. 
Fam. 2. Ascidiidae.—Solitary fixed Ascidians, never forming 
colonies ; with gelatinous or cartilaginous test ; branchial aperture 
usually eight-lobed, atrial aperture usually six-lobed; branchial 
sac not folded; internal longitudinal bars usually present; stig- 
mata straight or curved; tentacles simple; gonads in or around 
the intestinal loop. This family is divided into three sections :— 
Sub-Fam. 1. Hypobythiinae.—Branchial sac with no internal 
longitudinal bars, test strengthened with curious symmetrically 
placed nodules. 
The one genus Hypobythius, Moseley, contains two stalked 
deep-water forms found by the “Challenger ;” HZ. calycodes (Fig. 
34, A), from the North Pacific, 2900 fathoms, and H. moseleyr 
from the South Atlantic, 600 fathoms. 
Fic. 34.—A, Hypobythius calycodes, Moseley ; B, Chelyosoma macleayanum, Brod. and 
Sowb. ; C, Corynascidia suhmi, Herdman ; D, Rhodosoma callense, Lac.-Duth. 
Sub-Fam. 2. Ascidiinae.—Internal longitudinal bars present; 
stigmata straight. Many genera, of which the following are the 
more important:—Ctiona, Fleming, dorsal languets present ; 
Ascidia, Linnaeus (in part Phallusia, Savigny), dorsal lamina. 
