568 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
Mantle rather thin; its musculature not greatly developed. 
Tentacles rather large, and not very numerous; at least two sizes, 
arranged with some regularity. 
Dorsal tubercle small, horseshoe-shaped, the open interval directed 
forward. 
Dorsal lamina a broad membrane whose margin is raised into small, 
quite regular, narrow teeth. 
Branchial sac with four well developed folds on each side and very 
numerous internal longitudinal vessels. The first folds are a little 
the highest, the second and third about equal, the fourth decidedly 
lower. It is impossible to decide just how many vessels should be 
reckoned as belonging to the folds or to the interspaces as the folds 
begin so gradually, but the following schemes show their approximate 
distribution : 
Left side 5 (23) 5 (18) 3 (16) 3 (11) 5 
mch. en. 
Right side 3 (24) 5 (19) 5 (17) 5 (10) 5 
There are four orders of transverse vessels even in the dorsal part 
of the sac. The smallest merely cross the stigmata. On the inter- 
spaces from five to seven stigmata intervene between the internal 
longitudinal vessels; close to the endostyle and median dorsal vessel 
a greater number (ten or more) intervene. 
Stomach short and rounded, with a rather small number of longi- 
tudinal folds. No pyloric caecum was observed. Intestinal loop 
small and short; margin of anus with about ten rounded lobes. 
Gonads consisting of irregularly curved tubes somewhat constricted 
into a neck at the dorsal end, having a central ovary and peripheral 
testes, the latter small but generally cleft into several lobes. Their 
ducts unite and run along the ovary, ending in a papilla beside the 
opening of the ovary. The ovarian opening is lobed. The gonads 
are rather numerous on each side of the body, seven or eight on the 
right and at least six on the left. 
There is but one specimen in the collection, from Station 2466 (N. 
lat. 45° 29', W. long. 55° 24', 67 fathoms, coral). 
Its identity with Polycarpa finmarldensis Kiaer (1893) seems clear. 
This rare European form, said to be blood red when alive, is known 
only from the Norwegian coast. Sars (1851) first called it Ascidia sp. 
and later (1858) Cynthia gutta Stimpson. Sars's specimens were 
