CEPHALOPODA. 3 
dibles; reflexed externally, forming a ring around the fleshy 
part. Legs eight or ten, surrounding the mouth, their inner 
aspects furnished with suckers. Eyes two, lateral, perfect. 
Sae furnished with a cloaca, which is attached to the body. 
The sexes distinct. 
The sac contains the organs of respiration, digestion, circu- 
lation, generation, and a gland, common to all the genera, that 
secretes a black liquor, which can be ejected at the will of the 
animal. The sac is short and ovate in Polypus and Sepiola ; 
oblong, depressed, and rounded behind in Sepia; very elon- 
gate, pointed behind, and slightly depressed in Loligo. The 
fins are appendages of this sac; they are wanting in the first 
order, but are found in all the hitherto discovered genera of 
the second order; they are but little promment in Sepia, 
where they run down the whole of each side of the sac, and 
meet behind: they are very abruptly produced from the middle 
part of each side in Sepiola, and resemble wings; whilst in 
Loligo they arise high on each side, are immediately dilated, 
and gradually becoming narrow, unite at the posterior extremity 
of the sac. 
The organs of respiration resemble ferns, more or less dis- 
torted in the different genera; one is placed on each side of 
the interior of the sac. Plate I. fig. 5, B. 
The organs of digestion consist of a stomach or gizzard, a 
eeecum (or blind gut), and a large intestine terminating ante- 
riorly. The cesophagus, in Polypus, is dilated extremely at 
its lower extremity, before it enters the stomach, and is grooved 
internally ; whilst in Sepza it retains its original size, until it 
enters the stomach. The stomach of Polypus and of Loligo is 
very strong, deeply grooved within, and covered by a very hard 
substance ; that of Sepia is thin and very simple. 
The organs of circulation consist of three hearts: one cen- 
tral, whose office is that of general circulation ; and two lateral, 
one at the base of each gill, destined to perform pulmonary 
circulation. The central heart is somewhat semicircular in 
Polypus, and trilobate in Sepia. The lateral hearts have ap- 
pendices in Loligo, are simple in Octopus; whilst in Sepia 
there is a spongy, concave appendage, attached to the under 
B 2 
