MOLLUSCA; 201 
with extraneous bodies, or inclosing such. The branchial 
orifice has four rays, the anal one the same, or divided trans- 
versely. The branchiz are divided longitudinally into per- 
sistent regular deep folds. 
a. Body pedunculated. 
The peduncle, in this division, may be said to have its 
rise in the summit of the body, which it serves to suspend. 
The abdomen is lateral. The meshes of the branchi 
are destitute of papilla. 
Genus BourentA.—tThe tentacular filaments of the 
branchial circle are compound. There is no liver, and the 
ovarium is compound. Only one species is known, BP. fusi- 
forme. Savigny, Mem. tab. i. f. 1., and tab. v. f. 5. It is 
the Vorticella Boltent of Lin. and the Ascidia Clavata of 
Shaw. 
b. Body sessile. 
M. Savigny describes this group as a genus, which he 
terms Cynthia, which he divides into four sub-genera. 
(A.) Tentacular filaments of the branchial orifice com- 
pound. The folds of the branchiz more than eight in num- 
ber. The liver distinct, and surrounding the stomach. 
Ovarium divided, with one division at least on each side the 
body. The intestine destitute of a rib. 
Genus Cynruia.—Meshes of the branchiz unchanged 
by the folds. C. Momus. Sav. tab. i. f. 2. 
Genus Ca@stra.—Meshes of the branchiz interrupted 
by the folds. C. Diona of Sav. tab. vii. ff 1. The Ascidia 
quadridentata of Forskil. 
(B.) Tentacular filaments of the branchial orifice simple. 
The folds of the branchiz eight in number, four on each 
side, and the meshes uninterrupted. Intestine strengthen- 
