DOLABRIFERA. 117 
or absent ; radula with a well-developed median series of teeth, larger 
than the lateral teeth, and bilobed, spreading, at base. 
Four genera compose this subfamily, which is decidedly more 
allied to the Aplysiine than to the Dolabelline. The anterior inser- 
tions of the pleuropodia are contiguous, as in the latter group; but 
the dentition, and the forward situation of the genital orifice agree 
with Aplysiine. 
Genus III. DOLABRIFERA Gray, 1847. 
Dolabrifera Gray, P. Z. S.,1 847, p.162; type Dolabella dolmbre: 
fera.— Aplysia and Dolabella of some authors.—? Thallepus Swains., 
Malacol., p. 250, 359.— Dolabrifer FiscHer, Man. Conchyl., p. 568. 
General form ovate-oblong or sack-like, tapering toward the head. 
Tentacles and rhinophores slit and expanded distally, the latter 
nearer to the front margin than to the dorsal slit. Eyes as in 
Tethys. Pleuropodial lobes arising far behind the middle of length, 
contiguous, scarcely mobile, united behind, enclosing a large gill- 
cavity ; dorsal slit short. Mantle small, not perforated over the 
shell, nor covering much of the gill. Foot broad, often expanded 
at the edges. . Genital pore in front of the gill, under the mantle- 
edge. 
Shell small, not spiral, solid and calcareous ; subtriangular, trape- 
zoidal or irregularly oblong; the apex projecting and calloused, 
with no spiral tendency. 
Radula with large, subtriangular rhachidian teeth, with several 
denticles on the cusp; lateral teeth with long, coarsely denticulate 
cusps (see under D. ascifera). 
Type, D. dolabrifera Cuvier. 
Distribution, tropical shores in both hemispheres; one species 
from Greenland. 
This genus is allied to Petalifera in external characters and the 
solid, calcareous shell; but it differs in having the mantle completely 
closed over the shell, while in Petalifera there is a large orifice ex- 
posing part of the shell. Dolabella resembles Dolabrifera in the 
form of the body, short posterior branchial slit, etc., but it differs 
radically in the dentition, the position of the female genital orifice, 
and the spiral apex of the shell. . 
A considerable number of’ species are known more or less per- 
fectly from the Indo-Pacific area, with a few from tropical America. 
