206 =A. E. Verrill— Mollusca of the New England Coast. 
forming an elongated channel; it is distinctly visible from the out- 
side, owing to the translucency of the shell. 
Length of shell, 3°5™™ ; breadth, 2°5™"; height, about 1™”. 
Station 2105, N. lat. 37° 50’, W. long. 73° 03’ 50”, in 1395 fathoms 
(No. 38,072). ‘T'wo specimens, living. 
The animal has a short, broad-ovate foot, subtruncate in front, 
with the edge frilled. Frontal disk rather large, broad, semicircular 
or crescent-shaped, with the angles extending back in a large obtuse 
lobe on each side. Buccal area semicircular; mouth surrounded with 
four convex elevations, one before and one behind it, and one on 
each side. Tentacles slender, tapermg, acute. Eyes apparently 
wanting. No cirri on mantle. 
POLYPLACOPHORA, 
Placophora (Euplacophora) Atlantica Verrill and Smith, MSS. 
Verrill, Amer. Journ. Sci., vol. xxiv, p. 365, Nov., 1882. 
PLATE XXX, FIGURES 1, 1a, 10. 
Outline broad-ovate. Marginal membrane very broad anteriorly 
and narrow posteriorly. It increases gradually from the posterior 
end to a pomt oppostie the f’th plate, where it suddenly expands 
into a broad round front, wich the breadth one-third greater than the 
greatest breadth of the shell, and projecting forward to a distance 
equal to one-balf the length of the shell. The marginal membrane is 
thick, leathery, aud scabrous, everywhere closely covered with 
minuie spinules; the lower surface anteriorly shows many radiating 
grooves (not distinct in the smaller examples); between these are 
rows of slightly raised small verrucze, covered with small spinules. 
The inner edge, or mantle-border, is sharply defined, enclosing an 
elliptical area around the head and gills, with a well-marked poste- 
rior sinus; its front edge is divided into about seven digitations, the 
anterior ones rather long, tapering, and tentacle-like, but coriaceous 
and covered with fine spinules, like the rest of the marginal mem- 
brane. Cephalic hood ijarge, broad-lunate ; foot relatively small, 
ovate. Gills numerous (in the largest about sixteen on each side), 
extending nearly the whole length (more than two-thirds) of the 
foot, but reaching neither end of it. 
The shell is broad-ovate, slightly carinated in the middle; valves 
short, broad, the posterior ones decreasing rapidly in breadth, the 
last one very small. Anterior valve short, very broadly rounded in 
front; posterior edge with a very obtuse reéntrant angle and a 
