RETORT ON THE TUNICATA. 197 



Body attached, sessile, usually oblong or ovate in shape. Branchial aperture 



eight-lobed, atrial six-lobed. 

 Test cartilaginous, but soft and flexible, sometimes thin and membranous; rarely 



prolonged into hair-like processes, or covered with sand. 

 Branchial Sac never folded, sometimes minutely plicated. Internal longitudinal 



bars present, and usually papillated ; stigmata straight. 

 Dorsal Lamina in the form of a plain, or mure or less ribbed and pectinated 



membrane. 

 Tentacles simple. 



Viscera placed upon the left side of the branchial sac. 

 Genitalia in the intestinal loop. 



Whether the present genus should be called Ascidia or Phallusia is now a matter of 

 individual opinion, and it makes little difference which name is finally adopted. Ascidia 

 seems preferable for two reasons: — (1), it was the name first given, although in a wider 

 sense than as at present used ; (2), it has been more generally employed than Phal- 

 lusia. 



Baster, in 1762 (Opuscula subseciva, vol. i.), gave the name Ascidium to a species of 

 Simple Ascidian. This was afterwards changed by Linnaeus to Ascidia, and under that 

 name all the Simple Ascidians are grouped in the 12th edition of the " Systema Naturae," 

 and in 0. F. Midler's " Zoologia Danica." 



Savigny, in 1816, divided Linnseus's Ascidia into the four genera — Phallusia, Cynthia, 

 Boltenia and Clavelina. Of these Phallusia most nearly corresponds with the present 

 genus, but had wider limits, including the entire family Ascidiidse. Since Savigny's time 

 Ascidia has been used by some authors and Phallusia by others. 



The main objection to using Ascidia is, that when first proposed it included more than 

 what we now include in the genus, but this same objection holds in regard to Phallus/'" 

 also ; as used by Savigny, the latter term comprised Cwna and Corella, and was exactly 

 ecpuivalent to Ascidia as used by Forbes in his " British Mollusca" (1853). In precisely 

 the same sense, Ascidia has been used since by Alder in 1863, and by Claus in 1876, 

 and Phallusia by van der Hoeven in 1856, and by Kupffer in 1870. 



Hancock (1870) employed Ascidia in the restricted sense in which it is used here, 

 and has been used by Heller and others ; while Phallusia in the same restricted sense 

 (i.e., not including Ciona and Corella) has been employed by Kupffer in his " Jahresber. 

 der Commiss., &c," 1875, and by Traustedt in 1880. 



Hence it appears that whether we take the name first applied without regarding the 

 limits of the genus, or merely the name that was first used in the present restricted sense, 

 we find that Ascidia has the priority over, and has been rather more generally accepted 

 than, Phallusia. 



