548 Mr. W. S. MacLEAY’s Anatomical Observations 
Tentacula about twenty-six, simple, subulàte, alternately long 
and short. 
Anterior nervous tubercle with many spirals. 
Branchial cavity occupying the whole length of the animal. 
Pharynz situated at the bottom of the cavity of the body. Œso- 
_phagus descending, and turning short round near the cardia 
into a cylindrical horizontal stomach, which is striated ex- 
ternally, and occupies with the pylorus (which turns round 
and lies parallel to it) the whole of the bottom of the cavity. 
Intestine very long. Rectum ascending, almost vertical, 
terminated by an anus margined. | 
Ovary one, situated on the left side, between the branchial pouch 
and the tunic. It consists of a trifurcated, cylindrical stem, 
having at the base, on one side, a forked branch, on the 
other a simple one, all of the same thickness. 
^ This is a very singular animal in outward appearance, as it 
presents to the simple view no external orifices, and is shaped 
very much like an acorn. It appears to have been attached to 
some. small pebbles by its base, some of which remain aggluti- 
nated to it, and give it a wrinkled appearance below. The upper 
part of it is coriaceous, rather smooth and subpellucid ; for on 
compressing the body between the finger, the three branches of 
the ovary are very distinct. The colour of our specimen in spirits 
is cinereous. The top of the cylindrical body is rather flat, but 
rounded off at the sides. On applying a very strong power, we 
observe, at least in the only specimen I have had the means of 
examining, four apertures. Two of these are so large as to be 
visible with the naked eye, but are not the branchial and anal 
orifices, which are exceedingly minute. The two false apertures 
form a triangle with the branchial orifice, the space between them 
being rugose. The first is a semicircular cleft, which I believe to 
= be 
