67 
Kidderia campbellica n. sp. 
(PI. II, figs. 42—44, 56.) 
Shell small, oblong, a little narrower at the anterior end, in- 
flated, yellowish-gray and brown. Beaks a little produced, broadly 
rounded, situated a little above the front end which projects, nar- 
rowly rounded, below them. Basal margin slightiy curved, posterior 
end broadly rounded, dorsal margin evenly convex. Sculpture faint 
irregular lines of growth; besides these a trace of some radial lines 
or rugations in the median part of the shell; a faint dorsal ridge 
(indistinct in old specimens) extends diagonally from the umbones 
to the dorso-posterior margin. Colour yellowish-gray, posterior 
and dorsal parts usually dark-brown, interior grayish-white, usually 
brownish posteriorly and dorsally. Interior surface grainy, only 
edges without the pallial line smooth and shining. Margins smooth, 
Sharp. Ligament external, very long. Hinge perfectly tooth-less. 
Anterior adductor scar subcircular, smaller than the oblong poste¬ 
rior one and distinctly impressed. Dimensions: L. 6.5, h. 4.5, br. 
3 8 mm. — Locality: Campbell Island, 45, numerous sps. 
Externally the new species has a great resemblance to K. bi- 
color V. Mårtens (from S. Georgia), but that species is more 
elongate (with subparallel margins), and the new species differs 
from it and from any other species of the genus (thus also from 
K. pusilla) in being edentulous even in young stages of growth; 
only in one small specimen of 2.5 mm length a very indistinct 
right Cardinal tooth was observed. 
The animal has a very short pedal slit of the mantie, its length 
being smaller than the diameter of the anterior adductor. In K. 
bicolor this slit is twice that diameter. The pedal opening has 
smooth margins, then follows a long suture and, posteriorly, the 
large branchial slit with finely papillate margins and, above it, the 
anal slit with smooth margins. Between the two openings a pair 
of small papillae or tentacles are visible. 
Many of the specimens collected contained fry in their giils, 
but such were observed only in the inner giil on each side, and 
in small number. In K. bicolor, on the contrary, both demibranchs 
at each side serve as brood-pouches and contain numerous young, 
as made evident by examination of specimens from S. Georgia. Also 
in K. campbellica, however, there is a free communication between 
