10 W. A. HERDMAN. 
the description given by Michaelsen (JB. Hamburgisch. wiss. Anstalten, XXV., 
2 Beiheft, 1908, p. 250). H. clavigera has been recorded from various parts of the 
South American coast, Peru, and Chili. 
The photograph from which the larger figure (Plate IV., fig. 7) is taken 
represents the single specimen about twice the natural size. 
BOLTENIIDA. 
BoLTENIA SCOTTI. 
(Plate VII., figs. 1-11.) 
Locality.—Winter Quarters, in McMurdo Bay, Feb. 1902. 
External Appearance.—Stalk from one-half to three times as long as body, 
attached by an expanded base to a fragment of stone, and tapering slightly upwards 
(figs. 1, 3, 5). Body rather longer than broad, of ovate sub-cylindrical form, the 
anterior end, where the stalk is attached, being the wider. Apertures distant, the 
branchial being nearly under the stalk (figs. 1, 3) and the atrial in the middle of 
the free posterior end of the body; both apertures sessile and cross-slit (figs. 2, 4). 
Surface of the body finely roughened all over with minute papille, ending in sharp 
spines (figs. 7 and 8); surface of stalk corrugated or wrinkled. Colour grey, nearly 
opaque ; stalk rather yellowish. Size of largest specimen (fig. 1) :—Body 1°5 em. long, 
1 cm. broad; stalk nearly 4 em. long. 
Test, thin but tough. The roughness on the outer surface (fig. 11) is seen 
under the microscope to be due to closely placed, minute, sharp-pointed spines 
(fig. 8) of a yellowish tint. Round the apertures the spines are depressed and point 
radially outwards (figs. 4 and 6). 
Mantle thin, but moderately muscular, closely adhering to the test. The thin 
muscle bundles are in most parts arranged with regularity, so as to form quadrangular 
meshes. 
Branchial Sac with six folds on one side and seven on the other. There are 
seven to ten bars on a fold, and one or two in the interspace between (fig. 10). 
Dorsal Lamina composed of a series of short triangular languets, united by their 
bases to a wide membrane (fig. 10). 
Tentacles compound, about eight larger, rather slender and feathery, and some 
much smaller ones between. 
Dorsal Tubercle small, but prominent, on a rounded elevation ; cordate, with both 
horns coiled inwards (fig. 9). The long nerve ganglion is visible behind and to one 
side of the dorsal tubercle. 
Alimentary Canal very slender, forming a long narrow loop. Stomach globular, 
with longitudinal folds ; intestine narrow and straight for the greater part of its length. 
Gonads small, on both sides of the body. 
