704 CLASS XI. 



Note. Here also is to be referred sub-genus Amaroucium EDW. (better, 

 perhaps, Amareucium from d/iapetfw, on account of the channelled canals 

 that permeate the common body like cloacce or sewers). Sp. Amar. proli- 

 ferum MILNE EDW. Observed, s. 1. Asc. comp. PI. I. fig. 3, Amar. aureum 

 MILNE EDW., Cuv. R.Ani., ed. ill.. Moll. PI. 130, fig. i, Parascidia MILNE 

 EDW., a new genus different from all its congeners by the octoradiate bran- 

 chial orifice: R. Ani. ibid. fig. 3. 



Distomus G^ERTN., Distoma SAV. (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 GARTNER, PALL. Spicil. Zoolog. Fasc. x. Tab. iv. 

 fig. 7 a. A, &c. 



Sigillina SAV. 



Synoicum PHIPPS, 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, 4to, pp. 199, 200, PI. xm. fig. 3, SAV. Mem. 1. 1. PI. in. fig. 3, 

 PI. xv. 



Diazona SAV. 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., dd. i, Tab. xi. 

 fig. 6, eU 2, Tab. xiv. fig. 6, SAVIGNY 1. 1. PI. n. fig. 3, PL xir. 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. External 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 rtjdvov. 

 De Anini. Hist. iv. Cap. 6. LINNAEUS at first named this genus 

 Tethys, but confounded with it different animals which alone now 

 keep this generic name. BASTEB on that account gave to this genus 



