REPORT ON THE TUNIOATA OF PLYMOUTH. 57 



Musculature consisting almost exclusively of transverse fibres ; 

 longitndinal fibres rarely present except around the apertures. 



Branchial sac not folded, horizontal membranes absent or feebly 

 developed, replaced or surmounted by interserial rows of papilla3 ; 

 papillfe simple and unbranched or supporting incomplete or complete 

 internal longitudinal bars ; bars papillate or not papillate ; dorsal 

 lamina a longitudinal membrane or represented by a series of 

 slender languettes ; languettes rarely compressed from before back- 

 wards ; stigmata straight. 



Tentacles simple, filiform. 



Genitalia in the loop of the intestine ; oviduct and vas deferens 

 present. 



Reproduction by gemmation as well as from ova. 



This family includes the genera Perophora (Wiegmann), Pero- 

 phoropsis (Lahille), Slniteria (E. van Beneden), and Ecteinascidia 

 (Herdman, sens, strict.). In a complete system of classification it 

 should be placed very near to Roule's group '' Phallusidees,'^ which 

 embraces the genera Ascidiella, Ascidia, and Phallusia. 



A species of Ecteinascidia {E. Moorei), quite recently described by 

 Herdman, appears from his figures to possess dorsal languettes 

 flattened antero-posteriorly, and this is implied, though not directly 

 stated, in the text of his paper. This condition of the languettes is 

 unique within the family, and affords an approach towards the genera 

 Rhopalopsis, Rhopalsea, &c. 



3. Perophora, Wiegmann. 



Ascidia, Lister. Some Observations on the Structure and Functions of Tubular 

 and Cellular Polypi and of Ascidiaj, Phil. Trans., pt. ii, 1834, 

 pp. 378—382. 



Pebophoba, Wiegmann. Jahresbericht, Archives, 1835, p. 309. 



Ascidia, Fleming. Molluscous Animals, Edin., 1837, p. 202. 



Peeophoea, Forhes and Hanley. Brit. Moll., 1853, p. 28. 



— Adams. Genera of Mollusca, 1858, ii. p. 596. 



— Giard. Recherches, 1. c, p. 615. 



— R. von Brasche. Die Synascidien, 1883, p. 8. 



— Herdman. Tunicata, Encycl. Brit., 9th edit. 



— Cams. Prodr. Faun. Med., 1890, ii, pt. ii, p. 476. 



— Serdman. On the Genus Ecteinascidia, 1. c, p. 161. 



Zooids quadrangular or oblong, rarely pyriform, never cylindrical, 

 generally compressed from side to side. 



Test thin, membranous, without sterile stolonial tubes ; apertures 

 apart. 



Branchial sac rarely provided with rudimentary horizontal mem- 

 branes ; interserial papillae triangular or tubular ; papillee simple or 



