720 
Proceedings of the Royal Society 
ovary on the left just as in Clavelina. The branchial sac, however, 
is provided with strong papillae. The dorsal lamina finally is formed 
of languets. 
This is a very interesting form, being clearly intermediate in its 
characters between Clavelina and Ciona. The external shape and 
the condition of the dorsal lamina would allow of its being placed 
in either genus. The presence of thorax and abdomen, and the 
position of the heart and ovary, ally it to Clavelina , while the lobes 
round the branchial and atrial apertures, and the papillae on the 
branchial sac, show its relationship to the AscmiADiE. Finally, the 
bud-like projections from the test, a careful investigation of which 
would have been valuable, seem in the figure very like young 
individuals, and, if they are so, indicate gemmation probably from 
the blood-vessels of the test. 
Adams* in 1858 placed Philippi’s Rhopalcea in the old genus 
Clavelina. This, I think, is quite wrong. Clavelina has no lobes 
round its apertures, and no papillae on its branchial sac, while 
Rhopalcea has both ; still the fact showed that the resemblance of 
this form to the Clavelinid^i was detected, although it had been 
described by Philippi as a Simple Ascidian. 
Bronnf (1862) follows Milne-Edwards, and divides the Ascidice 
into simplices, sociales , and composite. 
Claus | (1876) unites the Ascidiad^e and the Clavelinid^e as one 
group, “ Einfache und aggregirte Ascidien ,” distinct from the com- 
pound Ascidians (Zusammengesetzte Ascidien). 
Professor Giard in his “ Kecherches sur les Ascidies Composes 
ou Synascidies ” § (1872) unites the Social Ascidians with the 
Compound, including Clavelina and Perophora in the Synascidioe. 
This he does chiefly on account of their property of budding, 
although he admits that budding alone is not sufficient to separate 
the Social from the Simple Ascidians. He gives as the charac- 
teristics of his Synascidioe || : — Reproduction by gemmation, stig- 
mata oval, the embryo being developed rapidly, and being almost 
complete before being hatched. 
* Genera of Recent Mollusca, vol. ii. p. 595. 
t Klassen und Ordnungen des Thier-Reichs, B. III. p. 216. 
X Grundziige der Zoologie, p. 840. 
§ Arch, de Zool. exper. et gen., vol. i. p. 501. 
|| Loc,. cit., p. 603. 
