FAMILY 3. APLYSIANA. 53 
The family of the Aplysiana may be divided into two genera, as tol- 
lows : 
APLYSIA. DovaBELLa. 
APLYSIA, Linneus. 
Testa interna, convexiuscula, subcompressa, tenuissima, cornea ; postice 
partum acuminata, vertice introrsim subrostrato ; anticé rotundata. 
The Aplysia depilans of Linneus, which may be regarded as the type 
of this genus, appears to have been one of the first of molluscous animals 
to attract the attention of naturalists. From its singular resemblance 
in form to a crouching hare, which similitude is increased by the ear- 
shaped structure of the tentacula, this mollusk has received the appella- 
tion of the Sea-Hare ; Lepus marinus of the Latins ; Aayo¢ Oadarrioc of 
the early Greeks ; and by the latter especially, as we learn from Nicander, 
the Aplysia was regarded with no little superstition. They believed that 
it exuded both a poisonous odour, and a poisonous liquor; and even 
Pliny has recorded instances of extraordinary credulity respecting certain 
properties assigned to this animal, which it would be only frivolous and 
unnecessary to notice. Although the subject of the present genus had 
been so long known, Rondelet seems to have been the first to give any- 
thing like a detailed account of it ; Linneus merely followed his descrip- 
tion, and little more was added until its complete anatomy was set forth 
in the elaborate memoirs of Cuvier and Rang; we cannot, however, be 
surprised that the ancients should have known but little of an animal 
which they regarded with so much fear and superstition. The Aplysiz 
were arranged by these authors with the rest of the naked mollusks; but 
as it was subsequently thought necessary to separate the water-breathing 
trom the air-breathing kinds, the Limacinea were referred to a distinct 
order, Pulmobranchiata, whilst the Aplysize and others were still further 
subdivided according to variations in the position or structure of the 
