REPORT ON THE TUNICATA. 233 



The dorsal lamina is a simple narrow membrane, projecting from the dorsal line of the 

 branchial sac, and having its surface in direct continuity with that of the neighbouring 

 vessels (PI. XXXVII. fig. 7, d.l). 



The dorsal tubercle is rather large (PL XX.W'II. fig. H, d.t.) ami lias the right horn 

 curved outwards, while the left is rudimentary. The posterior end is rounded, and the 

 anterior aperture is almost obliterated. The nerve ganglion is roundish or subtriangular, 

 and gives off numerous nerve trunks (PL XXXVII. fig. 8, n.g.). The neural gland 

 (n. (jl.) is large and ovate, and lies to the right side of the ganglion. It is connect ed 

 with the dorsal tubercle by a distinct duct. 



The viscera form an elongated mass on the dorsal edge of the branchial sac, below the 

 thickened part of the test, and are arranged very much as in Hypobythius calycodes. 



The single fragmentary specimen of Hypobythius moselcyi was obtained in the South 

 Atlantic, off the coast of Buenos Ayres, at Station 320; February 14, 1876 ; lat. 37° 17' S., 

 long. 53° 52' W. ; depth, 600 fathoms ; bottom temperature, 2°7 C. ; bottom, hard ground. 



Ciona, Fleming. 



Ascidia, Linnaeus, Sys. Nat., 12th Edit. 1766. In part. 



Ascidia, 0. F. MiiUer, Zool. Dan., vol. ii. 1780. In part. 



Phallusia, Savigny, Mem. Anim. sans Vert. Pt. ii. fasc. 1. 1816. In part. 



Ciona, Fleming, British Animals. 1828. 



Ascidia, Forbes and Hanley, British Mollusca, vol. i. 1853. In part. 



Ciona, Hancock, On the larval state of Molgula, &c, Ann. Mag. Nat. Hist, ser. iv. vol. vi. 



1870. 

 Ciona, Heller, Untersuch. ii. d. Tun. d. adriat. Meeres, Abth. ii. 1875. 

 Ciona, Kupifer, Jahresber. d. Commiss. 187"'. 

 Ciona, Traustcdt, Oversigt over de fra Danmark, &c, Ascidiae Simplices, Kj0benhavn. 1880. 



Body sessile, attached ; branchial aperture eightdobed, atrial sixdobed. 



Test gelatinous or cartilaginous, but soft. 



Mantle with the musculature chiefly in the form of a small number of distinct 



longitudinally running bands. 

 Branchial Sac not plicated; internal longitudinal bars papillated ; stigmata 



straight. 

 Dorsal Lam in" in the form of languets. 

 Tentacles simple. 

 Intestine lying on the left side of the body, and extending beyond the branchial 



sac posteriorly. 



Savigny, in his " Memoires," divided the genus Phallusia into three tribes: — 

 the Phallusia! Pireme, the Phallusiae Simplices, and the Phallusia? Cionas; the last of which 

 he characterised as having the branchial sac shorter than the mantle and the viscera 



