63 
this genus, which is the last of the Conchifera, 
only one species, L. anatina (Patella unguis. 
Lin.), is known. 
The Univalve Shells, or the Mollusca of 
Lamarck, commence in this Table. The Mol¬ 
lusca Pterofoda contain one family, viz. 
Hyalceana, which includes the genus Hyalaea; 
and the Mollusca Gasteropoda containing 
the families FhyUidiana, and Semi-Phyllidiana^ 
are likewise in this compartment. In the first 
are the genera Chitonellus, Chiton, or Coat of 
Mail shell, and the Patella, or limpet. In the 
second the genus Umbrella. 
Table 17 . Calyptracea, Bidlceana, Laply- 
siana^ and Limacina^ the four remaining families 
of the Gasteropoda. The genera of the Calyp- 
tracea are, Parmophorus, or Thracian shield 
shell, Emarginula, Fissurella, Pileopsis, Calyp- 
traea, Crepidula, and Ancylus. The Bullaeana 
contain the Bullaea aperta (Bulla aperta. Lin.), 
and several species of the genus Bulla. Lap- 
lysia and Dolabella are the genera of the next 
family. The shell of the former is a small 
cartilaginous scutcheon, which adheres to the 
posterior part of the back of the animal; that 
of the latter is wholly internal. The genera of 
the family Limacinaare, Parmacella, an internal 
shell, very rarely met with; Limax (the Slug), 
whose shell, a small testaceous lamina, is con¬ 
tained in a fleshy or coriaceous scutcheon, at¬ 
tached 
ROOM VIII 
Nat. Hist. 
