VAN NAME: SIMPLE ASCIDIANS. 
541 
ture exceptionally large, nearly round; atrial aperture smaller yet 
still of large size, and of the form of a transverse cleft. Ventral to the 
branchial aperture the anterior part of the body tapers rapidly off 
into the stem which arises from the anterior ventral part. (Its origin 
is continued as a ridjxe along the ventral margin of the body to near 
Text-flg. 27. — Culeolus suhmi Herdman. X f- 
the middle of the latter, where it ends abruptly.) Stem very slender, 
cylindrical, with minute longitudinal furrows; it ends in a slightly 
expanded base which breaks up into root-like fibers. 
Test moderately thin, tough, not wrinkled externally but thickly 
and evenly covered with minute rounded semitransparent tubercles 
each of which bears at its summit a still more minute nipple-like pro- 
jection. The tubercles are so abundant and evenly distributed that 
the surface of the body resembles sandpaper, but it is soft to the touch. 
On a few parts of the body closely crowded, slender irregular soft 
papillae are borne, some of them 1 mm. or even more in height. The 
larger of these papillae bear pointed yet soft projections or points 
along the sides. The points of the body where these papillae chiefly 
occur are about the margins of the apertures, and along a narrow line 
on each side which starts from a point on the dorsal surface near the 
middle of the body and passing obliquely downward and backward 
meets its fellow of the opposite side on the posterior ventral part 
of the body, where there is a considerable tuft or area of thege papillae. 
A few papillae are also scattered along the median ventral region. 
The alcoholic specimens are of a light yellowish brown color, the stems 
darker. 
Dimensions of three specimens: (1) body 60 mm. long, 37 mm. deep; 
stem 165 mm. long and about 1.5 mm. thick; apertures 45 mm. apart; 
(2) body 24 mm. long, 18 mm. deep, stem 100 mm. long, and .7 mm. 
thick; (3) immature, 14 mm. long, 11.5 mm. deep, stem 82 mm. long. 
