704 CLASS XI. 
Note.—Here also is to be referred sub-genus Amaroucium Epw. (better, 
perhaps, Amareucium from dmwapedw, on account of the channelled canals 
that permeate the common body like cloacw or sewers). Sp. Amar. proli- 
Serum Mitneé Epw. Observat. s. 1. Asc. comp. Pl. 1. fig. 3, Amar. awrewm 
Mrtne Epw., Cov. R. Ani., éd. ill., Moll. Pl. 130, fig. 1, Parascidiu MILNE 
Epw., a new genus different from all its congeners by the octoradiate bran- 
chial orifice: R. Anz. ibid. fig. 3. 
Distomus G&RTN., Distoma SAy. (a name to be rejected as pre- 
viously ascribed to a genus of Entozoa). Common body sessile, 
coriaceous, polymorphous. Several groups of animalcules. Ani- 
malcules divided into three separate parts. Six radii in the branchial 
and in the anal orifice. 
Sp. Distomus variolosus GHRTNER, Pauu. Spicil. Zoolog. Fasc. x. Tab. Iv. 
fig. 7 a. A, &e. ; 
Sigillina SAv. 
Synoicum Puirps, SAv. Common body erect, cylindrical, 
coriaceous, adhering by the base. Animalcules divided into three 
parts, elongate, arranged in a circular group at the incrassated apex 
of the common body. Branchial orifice with six equal rays, anal 
aperture with unequal rays, three larger and three small, subindis- 
tinct. 
Sp. Synoicum turgens PHIPPS, Voyage towards the North Pole in 1773, Lon- 
don, 1774, 4t0, pp. 199, 200, Pl. x111. fig. 3, Sav. Mém. 1. 1. Pl. 111. fig. 3, 
UX. 
Diazona SAy. Common body gelatinous, sessile, orbicular, 
excavated in the middle. Animalcules divided into three separate 
parts, arranged in several concentric series. Six equal rays at the 
orifice of the branchial and of the anal aperture. 
Sp. Diazona violacea Sav., Polyclinum diazona Cuv. R. Ani., éd. 1, Tab. xt. 
fig. 6, éd. 2, Tab. xiv. fig. 6, Savieny 1. 1. Pl. mu. fig. 3, Pl. xm. The 
entire system resembles a compound flower or an Actinia, and attains a 
diameter of six inches; the colour is a handsome violet. This species has 
been found in the Mediterranean on the Spanish coast. 
B. Simple Ascidians, solitary or associated by gemmiferous 
stolons. Hxternal integument sacciform, coriaceous or gelatinous, 
with two apertures approximate. (Genus Ascidia L.) 
The non-pedunculated sacciform species have been long known, 
and were well described by ARISTOTLE under the name of ry Avo. 
De Anim. Hist. tv. Cap. 6. Linyzxus at first named this genus 
Tethys, but confounded with it different animals which alone now 
keep this generic name. Basrer on that account gave to this genus 
