194 DESCRIPTION OF SHELLS. 
Belosepia longispina. (Tab. IX. fig. 12.) 
Callus perpendicular; spine elongated, horizontal; ventral plate semioval, 
short. 
Belosepia longirostris. (Tab. IX. fig. 15.) 
Callus much inclined backwards ; spine elongated, directed upwards ; ventral 
plate short and broad. 
Figs. a, a. are from two old specimens. 
Fig. b. represents what I suppose to be a young one of the same species. 
Beloptera, Deshayes. 
This genus has a strong affinity to Belosepia, but the ventral cavity, instead of 
being partly open as in that and in Sepia, is perfectly closed and conical with 
transverse septa as in Belemnites. I have seen no indication of a siphuncle in it, 
except a minute curve or sinus in the edge of each septum. ‘The oval wing-like 
processes, which help the resemblance to Belosepia, do not occur in both the 
known species, but rudiments of them may be traced in B. Levesquu. The species 
from Bracklesham is identical with that of the Paris basin. The anterior portion 
has never been found*. 
CEPHALOPODA TETRABRANCHIATA. 
Nautilus. 
Examples of the genus Nautilus occur in the clay at Bracklesham, but they 
are in so soft a state that perfect specimens have not been procured. I have not 
thought proper to place Nautilus ziczac under the genus Clymenia, although it 
might well be separated from Nautilus. Nautilus has an external shell, and 
there is no reason to suppose that N. ziczac differs in this respect from the 
typical species ; while Clymenia not only has a discoid shell, but in its struc- 
ture more resembles internal shells, and probably bears to Nautilus a relation 
similar to that borne by Scaphites to Ammonites ; and Scaphites is probably an 
internal shell, or at least partly so, for its form would not admit the animal to 
lodge in the terminal chamber. It would be speculating too deeply at present to 
arrange both Scaphites and Clymenia among the dibranchiate Cephalopods ; but 
their resemblance to Spirula might almost lead to that conclusion. 
* In a visit to Paris in 1847, I compared our Bracklesham Belosepie with those in the cabinet of 
M. Deshayes, and I am much indebted to him for his valuable remarks, as well as for several good 
specimens of Belosepia and Beloptera from the Paris basin.—F. D. 
