350 Dr. A. Arnbiick-Christie- Linde on a remarkable 
tudinal plications are visible in its wall. No pyloric cecum 
is visible. 
The intestine forms a short loop and afterwards bends 
upwards almost at right angles (text-fig. 3). As appears 
from the figure, the rectum is sbort and distinctly marked off 
from the intestine, from which it rises at right angles. 
The margin of the anus is provided with seven small 
lobes. 
The reproductive organs consist of one hermaphrodite gonad 
on each side of the body. ‘The gonad is of great length and 
characteristically bent into the shape of the letter U (text- 
fio. 4). In this individual it is well distended with eggs at 
different stages of development. Macroscopically no male 
glands could be observed, but from sections it appears that 
the gonad ‘contains very small glands—in all probability, 
male glands, though no spermatozoa were observed there,— 
with ducts, hidden by the mass of large eggs. So far as one 
can judge from this single specimen, the eggs and the 
spermatozoa are thus produced at different times. 
The ovary and testis each open at the end of the gonad by 
an elongated duct dorsally directed. Owing to the U-shaped 
form of the gonad, its distal end with the opening ducts 
almost touches its proximal end. The main sperm-duct lies 
upon the inner free surface of the gonad, and ends at some 
distance from the oviduct. Macroscopically the vasa efferentia 
were scarcely visible. 
Endocarps are present on the inner side of the mantle and 
in the loop of the intestine. 
Remarks. 
Ypsilocarpa clipeata is distinctly marked off from other 
species of Styelide by the characters of the gonads and the 
test. In no other described Arctic genus have the reproductive 
organs such an arrangement and number as in Ypsi/ocarpa. 
Though tubercles, elevations, spines, and other peculiarities 
of the test have often been described, no Arctic Styelid has 
yet been recorded with a test of similar structure, and no 
member of the group shows any other such point of agree- 
ment as would indicate close relationship to Ypstlocarpa. 
Styelids collected in other waters present no form com- 
parable with Ypsilocarpa, unless it be Styela squamosa, 
dredged to the south of Australia, and described by W. A. 
Herdman (1882, ‘ Challenger’ Rep. vi., Ascidiz simplices). 
According to that author (p. 152) the test of Styela 
