26 Memoirs of the Indian Museum. [Vor. Vile 
which alternate more or less regularly. The meshes are almost square and contain 
each five or six stigmata (Pl. V, fig. 1). Short, rounded knob-like papillae are found 
at the angles of the meshes. There are no intermediate papillae. 
The Dorsal Tubercle is horseshoe-shaped, simple, with both horns bent near the 
tip to the right (Pl. IV, fig. 12). 
The Dorsal Lamina is a simple narrow membrane, with no ribs and no teeth. 
The Alimentary Canal forms a simple loop on the left side of the branchial sac 
in the posterior half of the body (Pl. IV, fig. II). It consists of a short narrow 
oesophagus, an oval stomach, and a rather wide intestine bent in the form of the letter 
S. The stomach is smooth-walled, and the anal opening is smooth-edged. 
The Gonads form an elongated hermaphrodite gland placed inside the intestinal 
loop. From it a duct is seen to proceed along the first part of the intestine and the 
stomach, and then along the terminal portion of the intestine to open a little below 
the anus. 
Locality.—E.N.E. of Preparis Id., Bay of Bengal, at Station 61, 14° 54’ 30° N., 
93° 51’ E.; depth 41 fathoms; bottom sand, shell, and coral ; November 30th, 1880. 
One specimen. 
This species resembles in external appearance some of those Ascidiae already 
known which have thin transparent tests, but differs from all of them in the details 
of internal structure. It appears to be most closely allied to Ascidia aperta, Sluiter 
(13), obtained during the Siboga-Expedition, but the form and condition of the 
genital glands as well as the course of the genital duct are quite different. The form 
of the intestinal loop, too, is very unlike in the two species. 
Ascidia willeyi, n. sp. 
(Pl. V, figs. 2-5.) 
External Appearance.—The body is longish oval in shape, and is somewhat 
flattened obliquely (Pl. V, fig. 2). It is attached by the greater part of the left side 
and partly by the posterior end, and the edge of the base is in places expanded into 
a thin spreading margin. The apertures are both on the upper (right) side; the 
branchial is anterior and subterminal; the atrial is about half way down and at some 
distance from the dorsal edge. They are almost sessile, and the lobes, of which 
there are eight at the branchial and six at the atrial as usual, are very distinct. 
The surface is even, smooth, and naked. The colour is a pale horny tint. The 
size of the body: 35 mm. in length and 20 mm. in breadth. 
The Test is cartilaginous and transparent ; it is very thin on the left side, but is 
much thicker on the right. Fine blood vessels are seen everywhere traversing the 
test. 
The Mantle is thin and transparent. The musculature is only feebly developed, 
consisting on the right side of an irregular network of delicate fibres running in all 
directions, while on the left side there are scarcely any muscle fibres so that the 
internal viscera are very clearly visible (Pl. V, fig. 3). Even around the apertures 
the musculature is very weak, 
