ASCIDIA, 289 
An incision will reveal at once that the body of the 
animal is enveloped in a thick ¢es¢ (or /vnzc), out of which 
taberael the animal may be removed entire, like a bean 
out of its pod. ‘The test is thick and of a 
semi-transparent, gelatinous appearance. It 
is produced chiefly by the layer of underlying ectoderm, 
Features, 
Fig. 203. —DIAGRAMMATIC MEDIAN LONGITUDINAL SECTION 
THROUGH AN ASCIDIAN. 
Mouth. 
| 
& 
"eo 
S 
a 
oO 
v 4 a 
i 3 +-——~ Buccal Cavity. 
Subneural 4 5 
Gland. ra : 
Atriopore. AN i Peripharyn- 
r > = 2) geal Groove. 
oN 7 a Pharyngeal 
6 ae ai \ Clefts. 2 
= a 
Intestine. qo i -— Endostyle, 
Genital Fy 
Duct. 
4 ~~~ Pharyngeal part 
Atrium. of Ventral P 
os Vessel. 
Dorsal ; 
Blood-vessel.™ re 
Test, - \% 4 
(Cuticle). * ase Heart. 
Mantle X\ 
(Ectoderm). a 
ps: Gonad 
Stomach. Intestinal part of Ventral Vessel. 
The right half has been removed. 
andfconsists of a hyaline basis containing ce//ulose (a 
material mainly confined to the plant-kingdom), through 
which are scattered a number of cells. Below the 
M. 20 
