EEPORT ON THE THNICATA. 
103 
there is little or no bare patch at the summit of the colony, suggesting that the Asciclio- 
zooicls are rarely cast off ; and lastly, that there is not such a complete gradation between 
the buds at the top of the peduncle and the young Ascidiozooids at the base of the 
head. The buds are not produced in such numbers, and they probably go through 
their development as a whole more slowly than in the last species. The young Ascidio- 
zooids added to the base of the colony^ will therefore be fewer in number, and will occur 
at rarer intervals. Each Ascidiozooid in the head will live longer, and the death and 
decay of those at the summit will not occur so frequently. This of course only applies to 
a colony in a full grown and flourishing condition. When young the budding will no 
doubt be more rapid ; and when old the death of the Ascidiozooids and the decay of the 
colony will certainly increase greatly in its rate, and be accompanied by a diminution in, 
or entire stoppage of, the process of gemmation. 
Coldla gaimanli, n. sp. (PI. XIV. figs. 7-14). 
The Colony has the form of a more or less rounded mass, the head, attached by 
a peduncle. The head is usually flattened in one direction. The peduncle tapers 
downwards slightly to the point of attachment. The colour is dull yellow, jDassing in 
some parts into drab or brown. The surface is even and moderately smooth. No 
common cloaca! apertures are visible. 
The length of the head is 9 mm., the breadth 10 mm., and the thickness about 5 mm. 
The length of the peduncle is about 2 cm., and the thickness at the middle about 
2 mm. 
The Ascidiozooids are elongated antero-posteriorly, and are rather large, usually about 
3 mm. ill length and 1'5 mm. in greatest breadth. They are not arranged regularly. 
The abdomen is large and has a rounded posterior end from which a vascular 
appendage is prolonged through the common test. 
The Test is soft and gelatinous. The outer layer on the head is firmer and has a 
smooth glistening outer surface. It is very transparent. The homogeneous colourless 
matrix is crowded with cells of various sizes and shapes. A few very small bladder cells 
are present, but no pigment cells. 
The Mantle is fairly strong. The musculature is regular and well developed. It 
consists mainly of transverse bands. 
The Branchial Sac is delicate. The transverse vessels are rather narrow and are all 
of the same size. The stigmata are long and narrow. 
The Dorsal Lamina consists of a series of short pointed languets. 
The Tentacles are very short. There are eight, and they are all of the same size. 
The Alimentary Canal is large. 
