TUNICATA. 
99 
Fie. 19. 
colonies, which attain a length of nearly three feet. One end is 
attached, the rest of the colony apparently lying along the sea- 
bottom. 
Amaroucium roseum from Naples forms translucent gelatinous 
masses ; a slice is exhibited, showing the long slender ascidiozooids 
immersed in the mass. 
Pharyngodictyon miraUle (Fig. 18 C), from 1600 fathoms in the 
Southern Indian Ocean, resembles a small mushroom, and is about 
one inch in height. This species is one of 
the few deep-sea Compound Ascidians. 
Leptoclinum aloidum is a common and 
widely distributed species ; it occurs in the 
form of thin white crusts. The glistening- 
white appearance is due to the common test 
being densely crowded with minute stellate 
spicules of carbonate of lime. 
The specimen of Leptoclinum neglectum 
(Fig. 18 B) encrusts a fragment of sponge. 
Goodsiria pedunculata from the Straits of 
Magellan, forms a rounded cartilaginous mass 
attached by a short peduncle ; sometimes 
several masses are attached to each other. 
Each of the small dark oval areas on the 
surface corresponds to the branchial and 
atrial orifices of one ascidiozooid. 
Sub-order 3. — Ascid^e Salpiformes. 
The Salpiform Ascidians comprise only 
one genus, Pyrosoma, which occurs in the 
form of free-swimming colonies shaped like 
hollow cylinders closed and rounded at one 
end and open and truncate at the other 
(Fig. 19). The wall of the cylinder is formed 
of a single layer of ascidiozooids (Fig. 20), 
so arranged that all the atrial orifices open 
into the interior of the cylinder, and all the 
branchial orifices on the exterior, the two 
kinds Of orifices being at opposite ends of ^cyclopaedia Britannica.) 
the body, and not close together, as in most simple and compound 
Ascidians. 
h 2 
Pyrosoma elegans, natural 
size. A. Side view of 
entire colony. B. End 
view of open extremity. 
(Herdman : Tunicata, 
