VAX NAME: SIMPLE ASCIDIANS. 593 
Genus Corella Alder and Hancock, 1870. 
Body often raised on a stalk, branchial aperture with eight lobes; 
atrial aperture with six lobes. 
Test transparent, without horny plates. 
Branchial sac without folds but with internal longitudinal vessels. 
Stigmata arranged in spirals. 
Dorsal lamina with teeth or languets. 
Digestive canal on right side. 
Reproductive organs in the intestinal loop or spreading over the 
surface of the latter. 
Corella borealis Traustedt. 
PI. 65, fig. 123. 
1886. Corella borealis Traustedt, Dijmphna Zool.-bot. Udb., p. 423, pi. 36, 
figs. 1, 2; pi. 38, fig. 22; pi. 39, fig. 28. 
1891. Corella borealis Herdman, Journ. Linn. Soc. London, Zool., vol. 23, 
p. 588. 
1903. Corella borealis Hartmeyer, in Romer and Schaudinn, Fauna Arctica, 
vol. 3, p. 271. 
1909. Corella borealis Hartmeyer, Bronn's Tier-reich, vol. 3, suppl., p. 1393. 
There is but one small and mutilated specimen of this genus in the 
collection. It is insufficient for making a satisfactory identification 
or description, but such characters as can be made out, especially- the 
greatly reduced mantle musculature, indicate that it belongs to this 
species, rather than to the better known C. jxiraUclogramma which is 
widely distributed on the coasts of northwestern Europe. 
The body is oblong and may have tapered at one end into a stalk 
or pedicel, but if so, this has been broken off. The portion that re- 
mains is about 9 mm. long and 6.5 mm. deep, and appears to have 
been somewhat compressed laterally. Test thin, transparent, and 
practically colorless, its surface smooth except for some fine wrinkles 
and folds due to contraction. 
Musculature of mantle very slight, developed almost exclusively 
about the siphons and on the left side where it consists of a few (about 
a dozen) narrow bands extending transversely about halfway around 
the body. Several of these bands fork or divide into two branches 
in the ventral region. 
Tentacles numerous (perhaps fifty), slender and closely placed, of 
three sizes arranged quite regularly. 
