CEPHALOPODA. 9 
The specimen figured appears to be the same as the B. Bessinus, D’Orb., from the Inferior 
Oolite of Port-en-Bessin (Calvados) ; the general proportions are similar, about eight times 
as long as wide, and the division of the furrow may be faintly traced in some specimens. 
It is probably identical with the shell figured by Professor Buckman (loc. cit.) as B. cana- 
hicatus, Schlot., but that species is stated by M. D’Orbigny to have an equally impressed 
furrow, whereas, in our specimens, it is always expanded towards the point of the rostrum. 
Locality, The Stonesfield slate of Stonesfield, and Sevenhampton near Cheltenham. 
ORDER—TETRABRANCHIATA. Owen. 
Family—NavtTiLipa&. 
Naurtinus, Linneus. 
Brsreuttns, Oceanus, De Montfort. 
Ompuatia, De Haan. 
Navutiuites, Sehlotheim. 
A discoidal, convoluted, multilocular shell, compressed or ventricose, with contiguous 
volutions, the last one generally concealing the others, septa transverse, concave, and some- 
times sinuous, with entire margins, more or less centrally perforated in their disc. 
Navtiuus pispansus. Plate II, figs. 5, 5a. 
NV. Testé subglobosd, late umbilicatd, anfractibus rotundatis, lateraliter subcarinatis ; 
apertura dilatatd, subovali ; septis (2), siphunculo (?). 
A somewhat globose and smooth shell, with rapidly mereasing volutions, and a large 
and rather deep umbilicus, exposing the previous volutions ; umbilicus occupying about 
one third of the diameter of the shell; volutions rounded on the back, and slightly cari- 
nated towards the base by the obliquely flattened form of the outer margin of the 
umbilicus. Aperture expanded, arched, semi-ovate, wider than high. 
Septa and Siphuncle not visible in the specimen described. 
Diameter of the aperture ; 6 Finches 
Height of the qs 5 ; 33; 
Volutions increase in size (increasing pent 2 in the 
volution), from. : 24 to 63 in. 
Height of re-entering volution 1 RS 
This species is closely related to JV. excavatus, Sune » ‘Min. Con.’ tab. 529, f. 1, from the 
Inferior Oolite of Dorsetshire ; but it is readily distinguished from it by the more oval form 
of the aperture ; the width of the umbilical opening, in proportion to the diameter, is also 
