■<:::, . on the Natural Group of Tunicata. 547 



When the naturalist happens to consider that he ought always 

 to obtain his group before he attempts to find its character, he 

 is sure to perceive this truth ; and it is on this very principle, in- 

 deed, that Savigny, with his usual discrimination, has proceeded 

 in the above natural arrangement of the genus Ascidia, which I 

 have done little more than borrow from him. To this naturalist, 

 whose works I cannot too often recommend to the careful atten- 

 tion of zoologists as models for imitation and true examples of 

 the method in which Natural History ought to be studied, I 

 would willingly have dedicated the following subgenus ; but his 

 name happens to have been employed in other branches of the 

 science. On account of its ramose ovarium, therefore, I shall 

 name this .-jinni ::b fj 



Subgenus, DENDRODOA. 



External Character. Bodi/ subcylindrical, with both ori- 

 fices exceedingly minute and situated on the apex. 



Anatomical Character. Branc/iia/^owcA marked only with 

 eight folds, and having the reticulation continuous. Orifices 

 terminal. Tentacula simple. Liver none. Ovary unique, 

 branched, situated between the mantle and the branchial 

 pouch. 



i' Dendrodoa glandaria. 



D. glandiformis, tunica glabr^ sub-opac^. 



: Tab. XX. 



Descr. Body subcylindrical, with a rounded summit. Envelope 

 whitish, subpellucid, coriaceous and smooth, having its base 

 rough with agglutinated pebbles ; internally it has a pearly 

 lustre, and is thickest towards the base. Orifices so little 

 prominent as to be scarcely perceptible without a lens : se- 

 parate from each other, and opening with four indistinct 

 rays. Mantle muscular, but of uniform substance. 



VOL. XIV. 4 b Tentacula 



