VAN NAME: SIMPLE ASCIDIANS. 589 
vessels on the branchial sac. One fold is present on the right and none 
on the left side as in D. carnea. The fold bears a group of six to nine 
closely placed vessels; the remaining vessels of that side and those 
of the right side may be somewhat unequally spaced, or gathered into 
poorly defined groups, these groups probably indicating folds that 
have disappeared. They total (including those on the fold) about 
12 on the left and 13 or 14 on the right side in two of the larger speci- 
mens. In the largest specimen of all, their number and distribution 
may be written as follows, if we assume the grouping of the vessels 
to indicate rudiments of folds: 
Right side (7) (3) (4) (3) 
mdv. en. 
Left side (4) (4) (4) (4) 
One small specimen appears to have fewer (perhaps only ten) on the 
left side. Five to eight stigmata generally separate the vessels in the 
wider spaces. The transverse vessels of the sac are somewhat more 
numerous than in D. carnea, but the description of the rest of the 
anatomy of that species would apply equally well to these specimens 
so far as was observed, except that the folds in the stomach wall 
are more numerous, and only eighteen tentacles were counted in 
one individual in addition to a few small rudimentary ones. The 
dorsal tubercle is usually similar to that of D. carnea (in one specimen 
it was slightly crescent-shaped) ; the anus has tw^o lips. 
The writer believes that these specimens belong to this well known 
species, which is widely distributed in the waters of northern Europe 
and the adjacent parts of the Arctic seas, including the coasts of Great 
Britain and Ireland, Iceland and Greenland in depths down to 80 
meters, and which may therefore be expected to reach the northern 
part of our coasts. It is a variable species, occurring both solitary and 
aggregated into groups, and has been described in more or less detail 
by many writers. The reader is referred especially to the. w^orks of 
Julin (1892), Lacaze-Duthiers and Delage (1892), and Riedlinger 
(1902) for further details. 
The American specimens are from these localities: 
Gulf of Saint Lawrence, between Pictou Island and Cape Bear. 
Collected by J. F. Whiteaves. One specimen of very low flattened 
conical form, 12 mm. across, exclusive of the border of test substance 
