146 
NATURAL HISTORY. ^EAST. ZOOL. 
From the imperfect specimens of the animals of the ge¬ 
nus Spirilla which have been seen, and from the very 
small size of the terminal chamber, the tenuity of the 
structure, and the colour of the shell, there is every rea¬ 
son to believe that it will form a family of this order ; 
and if this should be the case, it is very probable, as the 
shells have the same texture, an equally small terminal 
chamber, and a very contracted mouth, that the fossil 
Ammonites , Scaphites , and other allied genera, will also 
be referrible to this order, or to a new one charac¬ 
terised by the developement of the shell, and regular 
syphoned septa. Their shells are to be distinguished 
from Spirula by the edge of the chamber being sinuated 
and the syphon placed near the dorsal surface. 
The Nautilophora have an oblong body inclosed in 
the cavity of the last whorl of a chambered shell, which 
has a tubular syphon passing through each of the cham¬ 
bers ; their eyes are slightly pedicelled, and they have 
numerous arms furnished with short tubular retractile 
tentacles and four gills. 
The family of Nautilidce have two series of very nume¬ 
rous tentacles, and a large fleshy appendage on the head, 
serving the animal as a foot for locomotion ; the shell is 
exterior, with simple concave septa between the chambers, 
and the syphon in the centre or near the inner edge. 
The family of Goniatidce are fossil shells, which only 
differ from the former in the septa between the chambers 
being flexuous or angular. 
The following Tables exhibit the series of genera of 
Mollusca at one view. 
Sub Kingdom. Fam. 2. Muricidce. 
Mollusca. a . Rane u a , 3. a. 
Class I. Triton, 3. b. 4. 
Gasteropoda. Persona, 4. 
Section I. Apollon, 4. 
Ctenobranchiata. Murex, 4. c. 
Order I. Zoophaga. CMcoreus^. d. 5. 
Fam. 1. Strombidce . Typhis, 6. 
Strombus, X. e. Pleurotoma, 7* 
Pteroceras, 2. a. b. Clavatula, 7* 
Rostellaria, 2. b. Conus, 7* 
Terebellum, 2. b. Fusus, 8. 
Pyrula, 8. 
Tritonium, 8. 
Struthiolaria, 8. 
Aporha'is, 8. 
d. Lathirus. 
Polygona. 
Turbineilus. 
Cynodonta. 
Fasciolaria. 
Cancellaria. 
Fam. 3. Buccinidaz. 
a. Cassis. 
Cassidaria. 
