496 Mr. Garner on the Nervous System of Molluscous Animals. 
the long cartilages mentioned above are not such, instead of spinal car- 
tilages. 
The brain of the Sepia (Tas. XXVII. fig. 2 &3.) consists of several parts or 
ganglia conjoined into a ring around the eesophagus, (from which it is only 
separated by a sort of dura mater,) and enveloped by the large cerebral carti- 
lage. Superiorly, upon the esophagus, we find the ring expanded into a lobe 
(fig. 2&3, A), cordate in shape, and giving in front four nerves (a.) to the 
labial ganglia (E.), and two bands (b.) descending to the anterior part (B.) of 
the lower division of the brain. The optic nerves (c.) arise from each side of 
thts lobe, and then swell into two large ganglia (F.), which subdivide into 
numerous filaments, piercing the coats of the eye, and forming the retina. 
This lobe is also continuous with the posterior part (C.) of the inferior por- 
tion of the ring by the broad band (c.). The anterior part of the inferior 
portion gives its nerves to the feet, as it does in the Gasteropoda to the undi- 
vided locomotive foot of those animals. The anterior and posterior parts are 
connected together, but not quite so intimately as they are in some Gasteropoda. 
The anterior part, besides the pedal nerves (d.), sends a band (e.) to the labial 
ganglion, as we saw it did in the Buccinum to the ganglia, which in that animal 
gave off both the labial and pharyngeal branches. Here the labial and pharyn- 
geal ganglia (D.) are distinct ; the latter being connected to the former by two 
nervous bands (fig. 1, 2 & 3, f.), as we saw in Patella. The posterior part of the 
inferior portion gives off the two branchio-visceral nerves (g.) ; more outwardly 
the nerves of the mantle (A.), the great agent in drawing in the water to the 
branchize of the animal; more outwardly still, nerves (7.) which mount over the 
superior lobe and supply the retractor muscles: it also, in the Sepia, gives off 
here the two nerves which supply the respiratory valves. The nerves going to 
the mantle are distinct from those which supply the siphon or funnel (7.), nuchal 
valve (k.), &c. There are three nerves for the siphon, and two for the lateral 
valves. The aorta separates the part affording the branchio-visceral nerves, &c. 
from the more anterior half of this part, giving siphonic nerves *. 
* The siphon is the expellent tube giving exit to the disaérated water, to the ink, feces, and se- 
cretions. In respiration the Cephalopoda, with an inhaurient sac, and a valve in their siphon or 
funnel to prevent the entry of the water by the wrong opening, and also valves at the sides of the 
neck, and base of the siphon, to hinder its escape by the wide opening for its entry; having likewise pro- 
tuberances on the inner surface of the sac, exactly fitting acetabula at the base of the siphon, for the 
