66 
Proceedings of the Royal Society 
end; posterior end large and flat, attached to a piece of coral; 
dorsal edge more convex than ventral. Branchial aperture anterior, 
at the highest part near the ventral edge ; atrial on the dorsal edge 
two-thirds of the way down; both are sessile and inconspicuous. 
Surface roughish, but regular. Colour dark reddish-brown. Length, 
1 *5 cm. ; breadth, 1 *2 cm. 
Test not thick but tough, white on the inner surface. 
Mantle very thin and membranous. 
Branchial sac with four slight folds on each side, about five 
internal longitudinal bars being crowded together, and the same 
number placed further apart alternately. Meshes elongated verti- 
cally, containing each three stigmata, divided by a narrow horizontal 
membrane. 
Dorsal lamina narrow. 
Tentacles simple, few, of a moderate size. 
Olfactory tubercle simple, nearly circular in outline. 
One specimen from Station 320 (off the coast of Buenos Ayres), 
600 fathoms. 
Styela squamosa, n. sp. 
External appearance. — Shape roughly hemispherical, the anterior 
end very large and rising somewhat to its ventral extremity ; 
ventral edge nearly straight, dorsal gently convex. Attached by the 
wide posterior end. Apertures sessile, distant, and inconspicuous ; 
branchial at the ventral end and atrial at the dorsal end of the an- 
terior extremity. Surface smooth but scaly. Colour creamy white, 
slightly yellow in parts. Length, 2 cm. ; breadth, 1 *5 cm. 
Test thick and solid, but soft. 
Mantle very thin, adhering slightly to the test. 
Branchial sac with two distinct folds on each side near the 
dorsal edge, and one or two more indistinct ones ventrally. 
Internal longitudinal bars numerous. Meshes slightly elongated 
vertically, containing each four or five stigmata, and divided 
horizontally. 
Dorsal lamina plain ; no ribs or teeth. 
Tentacles larger and smaller alternately. The larger ones are 
short and stout. 
