546 Mr. W.S. Macteay’s Anatomical Observations 
ANATOMICAL CHARACTER. Branchial pouch divided into lon- 
gitudinal folds, surmounted by a circle of compound 
or simple tentacula; the meshes of the respiratory 
apparatus destitute of papille. Abdomen lateral*. 
SYNOPSIS OF THE SUBGENERA. 
Normal group. SS 2 <7 oy Sere ss Reticulation of the branchial pouch 
1. Branchial pouch with more than Cynthies propres Say. continuous. 
eight folds. Tentacula com- | 2. CÆSIRA Sav. ........ Reticulation of the branchial pouch 
pound. Liver distinct, ... interrupted. 
( 3. STYELA Sav...,.....:. Ovaries several, one at least on 
each side of the body. 
4. PANDOCIA Sav. ...... Ovary unique, i. e. only the right 
Aberrant group. 
2, Branchial pouch with only eight 
folds. Tentacula simple. Li- 
ver NONE. ,.... 0000 
one, which is comprised in the 
intestinal loop. 
5. DENDRODOA mihi ..,. Ovary unique, i.e. only the left 
one, which is ramose or branch- 
ed, and situated between the 
E branchial pouch and mantle. 
The Tunicata agree with their contiguous group the Mollusca 
in the remarkable variation that exists in their system of genera- 
tion. Like every other solitary character that can possibly be 
adopted for the ground-work of a zoological system, the mode 
of generation ought to rise in importance only in inverse pro- 
portion to its degree of variation. In a group of animals, for 
instance, where it varies according to the species, it is evi- 
dently of less importance, as affording natural characters, than 
among those groups where it remains less subject to variation. 
* M. de Blainville seems not to have sufficiently studied these animals: for after 
giving an erroneous character to the genus Ascidia, and confounding it with the genus 
Phallusia and Clavellina, he ends with acknowledging, that with respect to the spe- 
cies “ leur distinction est assez difficile.” Art. * Mollusque; Dict. des Sciences Natu- 
 relles. Dr. Fleming has, on the other hand, given a very good view of this natural 
group in the art. * Mollusca’ of the Supplement to the Encyclopedia Britannica. 
: When 
