LABYRINTHUS.—ORTALICHUS. | 179 
L.. otis, however, apparently differs from L. plicatus in the longer and much narrower, 
channel-like projection of the peristome into the umbilicus, and in the bipartite 
internal and the bilobate external basal tooth of the aperture. 
Fam. GONIOGNATHA. 
Jaw composed of several plates, which are more or less soldered one to the other, 
but recognizable by their incumbent or free lateral edges at the lower margin. 
Teeth of the radula subquadrate, not spiniform. Shell generally bulimiform, longer 
than broad. 
This family contains chiefly American genera. 
ORTALICHUS. 
Bulimus, subgen. Orthalicus, Beck, Index Moll. p. 59 (1838); Albers, Die Helic. ed. 1, p. 171 
(first definition) (1850). 
Bulimi achatinoidei, Pfeiffer, Monogr. Helic. Vivent. ii. pp. 2, 148. 
Orthalicus, Troschel, in Archiv fiir Naturg. 1849, 1, p. 228; Shuttleworth, Notitiz Malac. i. 
p. 57; Pfeiffer, Monogr. Helic. Vivent. iv. p. 586; Albers, Die Helic. ed. 2, p. 224; Fischer 
& Crosse, Miss. Scient. Mex., Mollusca, i. p. 426; Strebel, Beitr. Mex. Land- und Sissw.- 
Conch. v. p. 1. 
Shell imperforated, longitudinally oval or rounded conical, with fine spiral lines, 
whitish or yellow, with dark bands, either spiral or vertical; the latter, termed streaks 
(strige), ordinarily bent zigzag, and often with some single black markings (varices), 
which are the remnants of a former peristome, when the shell was not yet adult. 
Whorls 6-8, steadily increasing. Aperture comparatively large, oval; peristome simple, 
not reflected, ordinarily with a narrow black edging ; columella nearly straight and thin, 
ordinarily white. Jaw composed of imbricate plates with very oblique lateral margins. 
Teeth of the radula in oblique rows, converging towards the lower edge in the middle, 
all provided-with a transverse broad blunt edge. 
This genus contains but few species, all of rather large size, and most of them 
beautifully painted. It is confined to the hot regions of America, from Florida and 
Mazatlan to Bolivia and the central portion of Brazil. The various species live 
ordinarily on trees, and some have been observed on dye-woods. ‘Those which live in 
Mexico and Central America are nearly allied inter se, and it may be questioned 
whether they do not run one into the other, so much so as to be regarded as varieties 
of one and the same species: most authors, however, including Shuttleworth, in his 
valuable Monograph, have treated them as distinct, and I adopt this plan; but I 
confess that in some cases it is very difficult to decide to which species a single 
specimen may belong. 
23° 
