40 THE AUSTEALIAN MUSEUM. 



Styela plicata, Lesueur. 

 (= Styela gyrosa, Heller.) 



There are 7 specimens from Port Stephen, 2 clumps of 3 indi- 

 viduals each and a solitary one ; and also a large clump from Port 

 Jackson, which measures about 16 cm. by 14 cm. by 7 cm., and contains 

 20 individuals more or less closely united by their bases. 



This species seems almost cosmopolitan in its distribution from 

 Australia to the Mediterranean. 



Styela Whiteleggii, n. sp., PI. Cyn. II., figs. 67; 

 PI. Cyn. XIV., figs. 16. 



External appearance. Shape elongate rounded, with the apertures 

 conspicuous, generally on prominent siphons ; body compressed laterally 

 and attached by the posterior end, which may be prolonged to form 

 branched rootlets. Surface a little grooved, or furrowed, but fairly even 

 and not roughened. Colour a dull yellowish grey-brown. Length 

 10 cm., breadth 6 cm., thickness 3 cm. 



Test coriaceous, tough but flexible, not thick, except at the posterior end. 



Mantle adhering to test, of a dark brown colour, very muscular and 

 rather thick. 



Branchial sac very large, with 4 folds on each side ; 6 to 10 

 internal longitudinal bars on the fold and about 12 in each interspace. 

 Meshes containing about 6 stigmata each, and divided by a narrow 

 horizontal membrane. The transverse vessels are of several sizes, 

 arranged with regularity ; an occasional very much wider transverse 

 vessel is present. Large oblique vessels run on the outer surface of the 

 branchial sac. 



Dorsal lamina a plain membrane, very slightly developed. 



Tentacles about 40, all rather large. 



Dorsal tubercle a slightly raised area of ovate form and spongy 

 appearance ; a number of small apertures scattered over it. 



Gonals a large branched mass on each side of the body. 



Locality. Port Stephen ; two specimens. Port Jackson ; seven 

 specimens. 



This large species is found in several cases associated with other 

 Ascidians. One large specimen has four individuals of Bolteuia ti/lcr- 

 culata attached to it (PI. Cyn. II., fig. 7). Another bears the only 

 specimen of Cynthia multiradicata (see PI. Cyn. IX.', fig. 1), and other 

 three are attached to Boltenias (PL Cyn. II., fig. 6). In some cases the 



