282 ON THE GENUS LUCERNARIA. 
the walls of the natatory sac, corresponding to the eight 
arms. 
The genus is probably confined to the northern seas; and 
in Europe the Channel, and in America Fundy Bay, 
appear to be its southern limit. Quoy and Gaimard, it is 
true, mention it as occurring at Toulon, but very vaguely, 
and later observers have never met with Lucernaria in the 
Mediterranean. 
The species of the genus have hitherto remained in consi- 
derable confusion, arising chiefly from the circumstance that 
that first observed by O. Fabricius has been regarded as 
identical with the one since described by J. Rathke under the 
same name. But this is now well known not to be the case, 
as I have satisfied myself, and as had previously been stated 
by Steenstrup and Sars. 
1. Lucernaria quadricornis. 
LL. quadricornis, O. F. Miller; Gmelin; Lamouroux ; 
Sars; v. Carus, Milne-Edwards. 
L. fascicularis, Fleming; Lamouroux; Ehrenb. ; 
Johnston; Frey and Leuckart. 
Char. Bell depressed, shorter than the stem. The elon- 
gated arms united into pairs, separated only at their extremi- 
ties, and each furnished with numerous (about 100) tentacles. 
Reaches 70 mm. in size. 
Hab. This, which is the largest of the known species, 
occurs throughout the coasts of Norway, in the Cattegat and 
Sound, also in North and South Greenland; on the east 
coast of North America; Faroe and Shetland Islands. 
Sars once noticed, among numerous specimens of L. quad- 
ricornis, one with a marginal papilla between the four arms ; 
whether this may prove a new species, Dr. Keferstein does 
not venture to decide. 
2. L. auricula, O. Fabricius. 
L. auricula, Gmelin; Sars; Steenstrup. 
Bell deep, infundibuliform, subcylindrical, with eight small, 
equidistant arms, between which are eight very mimute mar- 
ginal papillae. Stem as long as or longer than the bell. 
Length 40 mm. 
This species has till quite recently been confounded with 
others. Lamarck, Blainville, and Sars place it with L. guad- 
ricornis, whilst J. Rathke, Montagu, Johnston, and Milne- 
Edwards associate it with L. octoradiata, 
