368 MR. J. D. MACDONALD ON THE ANATOMICAL CHARACTERS 
stomach which curves gently downwards and backwards, and gradually diminishes in size - 
to the point where it becomes continuous with the intestine. The latter courses back- 
wards and then upwards on the right side of the body, until, having arrived opposite the 
branchial opening, it bends suddenly forwards, forming a simple loop, and again passes 
towards the stomach, above but parallel with its former course, to terminate in the cloacal : 
chamber close to the position of the mouth. ^ 
The liver is of a rudimentary character in this species, consisting of minute sacculations, 
which emboss the surface-of the stomach, and impart to it a rich amber or brown hue. 
The ovaria are two in number, one lying on either side of the body, between the 
branchial membrane and the muscular coat. The right ovarium does not occupy the lop | 
of intestine, as it does in Boltenia and most other Tunicata, but is placed in a recess in 
front. of it. 'These organs are pyriform in shape and laterally compressed, with the ` 
smaller end and the short duct issuing from it directed towards the cloaca. The testes | 
are also two in number, consisting of numerous . elongated and finely-divided lobules 
radiating round the base of the ovaria. | i : 
II. In Hamelin’s Harbour, Shark Bay, a second species of this genus, but of much larger 
size, is rather plentiful. Unlike that just described, it appears to lie loosely, or witha . 
very slight attachment; on the sandy bottom, being too massive to be supported on the 
delicate stem of a Zostera or an Amphibolis. - ; | | 
The body of the animal is somewhat rounded, compressed on the- sides, and averages - 
one inch and six-tenths in antero-posterior measurement, and one inch and three-tenths in 
the vertical direction. | | | | $ 
The test itself is very thin ; but numerous branched and interlacing fibres, often tubular, 
and containing prolongations from the mantle, arise from every part of its outer. surface, 
and form a matrix for the lodgement of shell and coral grit, foraminifera, and other extra- 
neous matters. -In this way the coat assumes a thickness of about one-fifth of an inch. 
The external openings lie nearly on the same plane upon the upper or neural surface; 
but they are usually so surrounded with small and irregular processes of the test, that it 
is difficult to determine their actual configuration; they are, however, connected by å 
straight fold of the test, as in the former species. 7 | ee 
The mantle presents an almost uniformly greenish-yellow tint, produced by minutely x 
divided and reticulated vessels. pn | | EE 
The fibres of the muscular coat are delicate, and rather loosely disposed over the general — 
surface of the body, though very strongly developed round the branchial and cloacal 
openings, in circular and radiating bundles. The lining membrane of the latter opening 
presents a rosy hue; and just within the margin of that which leads to the respiratory 
chamber spring several tentaculiform bodies, which appear to correspond with the dupli- 
catures of the contracted aperture. The true tentacula, however, always lie internal AE 
these or their modifications in the Tunicata generally. 
The tentacula in the present, as in the former species, are compound, consisting of a 
tapering central portion, with six or seven pairs of subramose lateral processes, openly set ` 
with minute papillæ. Both the axis and rami are crested or angulated in the middle; = 
