706 CLASS XI. 



(the figures relating to this memoir were also given, better executed, in 

 Pt. X. of the Nov. Act. Acad. Cces. Leop. Car. 1821, p. 423) ; W. S. MAC 

 LEAY Anatomical Observations on the Tunicata, Linn. Trans. xiv.i825, pp. 

 527555; PHILTPPI Rhopalcea ein neues Genus der einfachen Ascidien, 

 MUELLER'S Archiv, 1843, pp. 45 57 (which memoir contains some notices 

 on different simple Ascidians found by the author near Naples). 



A. External tunic gelatinous. Two orifices, either without 

 distinct rays, or furnished with more than four rays. 



Perophora WIEGM. Body compressed, sacciform, placed by 

 means of a short petiole on a creeping tube, connecting several 

 individuals. Branchial sac ample, produced to the posterior part of 

 body. 



Sp. Perophora Listeri, a small animalcule living socially, fixed on Conferva 

 elongata by a creeping, cirrus -bearing pedicle : found by LISTER on the 

 English coast, Phil. Trans, for 1834, Pt. 2, pp. 378382, PI. xi. In the 

 pedicle, connecting the animal, a double blood-current was observed. The 

 name Perophora is given to this genus of Ascidia by WIEGMANN in his 

 Report on the Advancement of Zoology in 1834, Archiv f. Naturgesch. 1835, 

 I. s. 309. 



Clavelina SAV. Branchial and cloacal pore without rays. Bran- 

 chial sac short, destitute of papilla, not plicated. Body oblong, 

 attenuate at the base, petiolate. 



Sp. Clavelina lorealis SAV., Ascidia clavata PALL., Spicil. Zool. x. Tab. I. 

 fig. 1 6, SAV. 1. 1. PI. I. fig. 3, PI. xi. fig. 2. In the North and Polar seas; 

 Clavel. lepadiformis SAV., Ascidia lepadiformis 0. F. MUELLER, Zool. 

 Dan. Tab. 79, fig. 5, MILNE EDWARDS Observ. VAsc. Tab. I. fig. i. Tab. II. 

 fig. i, &c. 



Sub-genus : Rhopalaea PHILIPPI. Branchial pore sexradiate, anal 

 octoradiate. Branchial sac short, beset with papillse, with transverse 

 striae subindistinct. Body elongate, clavate, petiolate, with covering 

 pellucid. 



Sp. Rhop. neapolitana PHILIPPI 1. 1. Tab. iv. 



Phallusia SAV. Body sessile, mostly oblong. Branchial pore 

 mostly with eight or nine radii, cloacal pore sexradiate. Branchial 

 sac not plicated, ample, descending to the bottom of internal tunic 

 or reflected at the bottom. 



Sp. Phallusia mammittata, Ascidia matiynillata Cuv. Mem. s. I. Ascidies. 

 PI. in. R. Ani., ed. ill., Moll. PI. 125, fig. i ; in the Mediterranean. The 

 thick, white, gelatinous, semi-transparent external tunic presents under the 

 microscope large oval vesicular cells, without nuclei; this species attains 

 a size of more than 4 inches, &c. 



