ORDER Ill. 
1. PLeuroprancuus. (1) 
Cuv. 
Body as if between two 
shields formed by the foot 
and the mantle; the lat- 
ter sometimes containing 
an oval calcareous plate. 
2. APLYSIA. (2) Lin. 
Edges of the foot turn- 
ed up, flexible, encircling 
the back in every part: 
head borne on a_ neck. 
Pl. 44, fig. 2,44* 14. 
( 60 ) 
GENERA. 
2 Tubulous and cleft 
tentacula on the mouth 
(a small trunk), sur- 
mounted by a lip. 
2 Superior tentacula, 
hollowed like the ears 
of a quadruped, with 
the eyes at the base ; 2 
others flattened and at 
the edge of thelower lip. 
TECTIBRANCHI. 
Branchie along the 
left side, in the furrow 
between the mouth and 
the foot. 
Branchiz on the back 
and attached to a stem 
covered by asmall mem- 
branous mantle, con- 
taining a_ hollow flat 
shell. 
3. DorasEetta. Lam. 
Body erga atrun- _— Ditto. Branchiz at the pos- 
cated cone; shell calca- terior extremity of the 
reous. body. 
4. Norarcnus. Cuv. 
Mantle with an oblique _Ditto. Branchie as in 4phy- 
cleft above the neck com- 
municating with the bran- 
chie. 
sla. 
(1) They have four stomachs; the second is fleshy, sometimes armed with bony 
pieces, and the third furnished interiorly with longitudinal projecting plates ; the 
intestine is short. 
(2) An enormous membranous crop conducts to a muscular gizzard, armed with- 
in by pyramidal, cartilaginous corpuscles, followed by a third stomach sown with 
sharp crooks, and a fourth in the form of a cecum: the intestine is yoluminous. 
These animals feed on fucus. A peculiar gland furnishes, by an orifice situated 
near the womb, alimpid humour, which is said to be sour in some species; a deep 
purple liquor issues abundantly from the edges of the mantle, with which the 
animal colors the water to a considerable distance on the approach of danger. 
When Apuleius was accused of magic and poisoning, it was reported as a principal 
evidence that he had engaged some fishermen to procure him an Aplysia (Sea- 
Hare) ; and it is to the following part of his description that we owe the only cha- 
racteristic which has enabled us to recognise so celebrated an animal. ‘ It has 
an extraordinary property, of which my predecessors have been ignorant, which 
is, that being otherwise destitute of bone, it has twelve small ones in its belly, 
similar to the astragali of the hog, attached and tied together.” The form of the 
Aplysia explains the name of Sca-Hare ; and their smell, and the liquor which they 
produce, account for the pernicious properties attributed to them. 
