166 MANUAL OF THE MOLLUSCA. 
suckers in two rows; the third left arm nectocotylised at the 
apex. 
Distribution, 2 species. Mediterranean. 
BouirHzna. Strp. 1858. 
Similar to Eledone, but more gelatinous, and with small 
suckers. 1 species living. 
SECTION B.—DECAPODA. 
Arms 8. Tentacles 2, elongated, cylindrical, with expanded 
ends. Suckers pedunculated, armed with a horny rmg. Mouth 
surrounded by a buccal membrane, sometimes lobed and fur- 
nished with suckers. yes movable in their orbits. Body 
oblong or elongated, always provided with a pair of fins. Funnel 
usually furnished with an internal valve. Oviduct single. Nida- 
mental gland largely developed. Shell internal; lodged loosely 
in the middle of the dorsal aspect of the mantle. 
The arms of the decapods are comparatively shorter than 
those of the octopods; the dorsal pair is usually shortest, the 
ventral longest. The tentacles originate within the circle of 
the arms, between the third and fourth pairs; they are usually 
much longer than the arms, and in cheiroteuthis are six times 
as long as the animal itself. They are completely retractile 
into large subocular pouches in sepia, sepiola, and rossia ; partly 
retractile in /oligo and sepioteuthis ; non-retractile in cheiroteuthis. 
They serve to seize prey which may be beyond the reach of the 
ordinary arms, or to moor the animal in safety during the 
agitation of a stormy sea. 
The lingual dentition of the cutile-fishes somewhat resembles 
that of the pterovoda. The central teeth are simple in sepia and © 
Fig. 39, Lingual teeth of Sepia officinalis (Cocken). 
sepiola, tricuspid in loligo, and denticulated in eledone. ‘The 
lateral teeth or uncini are three on each side, and mostly simple 
and claw-like. There were fifty rows of teeth in one specimen 
of sepia, the ribbon increasing in breadth from before to behind. 
