224 CLASS III]. GASTEROPODA. ORDER VII. PECTINIBRANCHIATA. 
Pl. CCLXI. Fig. 3. 
Monoceros LuGUBRE, Sowerby, Genera of Shells, No. 5. 
Purpura lugubris, Kiener. 
Pl. CCLXI. Fig. 4. 
Monoceros cincuLatuM, Lamarck, Anim. sans veri., vol. vii. p. 250. 
Encyclopédie Méthodique, pl. 396. f. 4. a, b. 
Turbinella cingulata, Kiener. 
CONCHOLEPAS, Lamarck. 
‘Testa ovata, spira parva, brevissima, anfractu ultimo latissimé inflato, ad 
basem leviter canaliculato ; apertura amplissima, teste magnitudinem 
zquante ; labro columellari, planulato, reflexo ; labro externo conti- 
nuo, processibus dentiformibus tribus obtusis ad inferiorem partem 
armato. Operculum corneum. 
One of the earliest plans of subdivision that presented itself to natu- 
ralists was that of simply separating the spiral shells from those in which 
there is no spire. The former, by far the more numerous, were classed 
under the common title of Cochlea or Conchs ; the latter. including the 
Patelle and such like, under that of Lepas or Rock Shells. Upon the 
discovery of the shell we have now to treat of, however, our forefathers 
were somewhat puzzled, for it scarcely exhibits a spire, though a spiral 
shell, being of a complete patelliform construction, with nevertheless a 
spire, not larger certainly, says Bruguiére, than a grain of corn. D’Ar- 
genville in this dilemma called it, after the fashion of his day, ‘‘ Le grand 
Concho-Lepas,” and that expressive compound has been used either as a 
specific or generic name ever since. Linneus regarded this shell, in the 
absence of its animal inhabitant, as a species of Patella, but upon the 
arrival of some living specimens from Peru, it was unexpectedly found 
to be pectinibranchiate, and onererlated. Bruguiére then removed it to 
