EEPOET ON THE TUNICA TA. 
•275 
cloacal apertures of small size, and surrounded by six lobes, occur frequently over the 
surface of the colony. The bodies of the Ascidiozooids are placed vertically in the colony, 
and are distinctly divided into two regions, thorax and abdomen. 
The Test is hard and brittle. It is white, and is opaque throughout. The matrix is 
structureless, and contains large numbers of calcareous spicules and of test cells. The 
latter are mostly fusiform, or triangular in shape. The spicules are stellate or spherical. 
They vary somewhat in size and shape. Vessels with swollen ends also occur in the test ; 
they are not numerous, but they occasionally branch near their terminations. 
The Mantle is thin and membranous. The musculature is feeble. 
The Branchial Sac is small, but the stigmata are well developed. There are four 
rows, separated by wide tranverse vessels. The stigmata are short but regular. 
The Endostyle is large and conspicuous. 
The Alimentary Canal is of considerable size. It forms a narrow loop placed behind 
the branchial sac. 
The Reproductive Organs are placed alongside the intestine. The testis is large, and 
the vas deferens is spirally coded around it. 
Locality. — Bahia, Brazd, September, 1873 ; depth, 7 to 20 fathoms. 
One large colony and several smaUer ones of this handsome species were obtained in 
shadow water off Bahia, on the east coast of South America. They incrust Sponges 
(PI. XXXVI. fig. 1) and other foreign bodies. 
In most cases the colony is a thin expansion attached throughout its entire extent, 
but in some of the smaUer colonies some parts become thickened and form projecting 
lobes (PL XXXVI. fig. 3 shows a section through such a thickened knob). The surface is 
always smooth and of a pure opaque white colour. The dimensions given above are 
those of the large, colony. The other specimens in the collection are alT considerably 
smaller. 
The Ascidozooids are distributed evenly over the surface of the colony, and their 
anterior ends show distinctly as small circular dots (PI. XXXVI. fig. 1). The common 
cloacal apertures are numerous but of very small size. Slight magnification with a 
lens allows the lobes surrounding both the branchial and the common cloacal apertures 
to be distinctly seen (PI. XXXVI. fig. 2, hr. and at.). In both cases there are six, 
and they are triangular in form, consequently the closed apertures have a stellate 
appearance. 
The abdomen of the Ascidizooid lies nearly directly behind the thorax, and is about 
equal to it in size (PI. XXXVI. fig. 3). It extends from one-half to three-fourths of the 
way from the upper to the lower surface of the colony, except in places where the test 
is especially thick (PL XXXVI. figs. 8 and 3); In such cases the thickening is in the 
test below the posterior ends of the Ascidiozooids. 
