100 CLASS III]. GASTEROPODA. ORDER VI. PULMOBRANCHIATA. 
HELICINA, Lamarck. 
Testa subglobosa, spira vel acuta, vel depressiuscula; apertura semi- 
orbiculari, marginibus disjunctis ; labro expanso, reflexo, fissura 
prope ad columellam interdum inciso; columella transversa, basi 
callosa. Operculum corneum, interdum subcalcareum, non spirale. 
The genus we have now to consider, Helicina of Lamarck, Oligyra of 
Say, presents a very natural assemblage of characters, and has acquired 
no little interest amongst modern conchologists on account of the many 
beautiful new species that have been contributed to it by recent disco- 
veries. Only one species appears to have been known to the early 
naturalists, figured by Brown in his excellent ‘ History of Jamaica’ under 
the indefinite title of Cochlea, and by Lister amongst the Helices ; four 
only are mentioned by Lamarck, but sixteen species were subsequently 
described by Gray in the ‘ Zoological Journal.’ This number, however, 
has since increased to between seventy and eighty, described at different 
times by Lea, Wagner, D’Orbigny, Guilding, Sowerby, Jun., &c.; and the 
whole are now presented by the last of these authors in his ‘ Thesaurus 
Conchyliorum,’ in the form of a well-illustrated monograph. 
Gray appears to have been the first to make any mention of the ana- 
tomy of the Helicine ; he certainly proves their affinity with the Cyclo- 
stomata, both in being operculated, and in having only two tentacula, and 
fully shows the inaccuracy of the situation to which they were assigned 
by Lamarck; namely, first with the Nerite, and afterwards with the 
Anostomata. This opinion is not, however, sanctioned by De Blainville, 
nor was it indeed by Cuvier ; for the Helicine are arranged by both these 
authors in another family, together with, and next in order to, the Am- 
pullarie. They undoubtedly supposed the Helicinz to be aquatic ; but 
D’Orbigny informs us that he found them in journeying through South 
America on open plains, as also upon the eastern side of the Andes, 
