56 MR. A. W. WATERS ON 
the mucro only occurs on the younger zoccia. In some positions 
the lateral spines are readily mistaken for a mucro. 
There is one small specimen from off Cape Mary Harmsworth 
which has no lateral or suboral avicularia, no spines, no scutum, 
and the median cell is not mucronate. There are two moderate- 
sized specimens from off Giinther Sound, on each of which I 
have found one lateral avicularium, while the other zocecia are 
unprovided with them. These specimens have no scutum, and 
one lateral spine. On the other hand, there are specimens from 
Cape Mary Harmsworth in which both the scutum and lateral 
avicularia are fairly constant, and there is usually one lateral 
spine. 
The absence of suboral avicularia seems to be general in the 
Arctic forms which I have had the opportunity of examining ; aud 
no authors except Busk and Smitt mention anterior avicularia 
on S. gracilis, Busk says: “anterior avicularium small, rare, 
and only (?) on the median zocecium at a bifurcation.” In 
specimens sent me from Varanger Fjord as J. gracilis var., 
there are a few anterior avicularia to the zoccia at the bifur- 
cation; but in these specimens there is to each zocecium an 
extremely large scutum and very large elongate ovicells besides 
very long spines, and probably it should be separated specifically. 
In no other case have I seen anterior avicularia. 
The radicle is attached to a raised chamber at the base of the 
zocecium, and in the specimens examined there are many zocecia 
to an internode. 
Specimens from lat. 77° 55’ N., long. 53° 20’ E., and those 
from Varanger Fjord have 16 tentacles. Busk says 12 tentacles 
to his specimen from Franklin Pierce Bay. S. elongata, Sm., has 
18 tentacles; S. Smittiz, Norm., 15 tentacles. 
There are two lateral rosette-plates to the entire side, and the 
distal wall has a number of small rosette-plates near the base. 
The mode of connection is similar to that obtaining in Serupo- 
cellaria, and that genus must be extended to receive this portion 
of the Menipea (auct.). The only difference is that there are no 
vibracule, but this is also the case in some typical Scrupocellaria, 
and in others they are rare. 
Loc. Spitzbergen, Greenland, Scandinavia, Kara Sea, Novaya 
Zemlya, Jan Mayen, Queen Charlotte Islands (H.), Labrador, 
Barents Sea, Franklin Pierce Bay ; lat. 79° 55’ N., long. 51° 0’ EH. 
(Ridley) ; lat. 79° 31' N., long. 68° 21' E., 230 met. (Marenzeller). 
