10 THE AUSTRALIAN MUSEUM. 



muscle bands, although of the usual number, are remarkably weak. 

 The alimentary canal is very clearly visible through the mantle (see 

 fig. 3), and is seen to extend unusually far forwards. The branchial sac 

 has very large papillae projecting from the internal longitudinal bars ; 

 these are relatively larger and more conspicuous than in British specimens 

 of the species. Figure 4 shows the dorsal tubercle. Many of the 

 specimens adhere together in groups by their posterior ends, and their 

 tests have grown together, but there is no reason to regard them as 

 forming colonies. Notwithstanding these few points of difference in 

 detail, I do not feel justified in separating the Australian specimens as a 

 new species. I find also in the collection one specimen of a Ciona (figs. 

 1 and 2) adhering, along with Colella tcniiicaulis, to the back of the 

 crab Macippe spinosa, Stimp. It is 2 cm. in length and 1 cm. in thick- 

 ness, and is in a greatly contracted state. There are also 3 small 

 specimens of Ciona adhering to Chorizoconniis subfuscus, from Port 

 Jackson. All of these specimens are more or less in bad condition 

 for detailed examination, but appear to be indistinguishable specifically 

 from Ciona intestinalis, Linn., although living material might show 

 differences. 



[The following Cioninae have also been recorded from Australian 



Ehodosoma, Ehrenberg, 1828. 

 B. (Pera) Huxleyi, Macdonald. 

 R. (Peroides) sp., Macdonald.] 



Sub-family ASCIDIIN^l, Herdman, 1882. 



Body usually attached by left side or posterior end. Branchial 

 aperture with at least 8-lobes, atrial with at least 6-lobes. 



Test gelatinous or cartilaginous. 



Mantle with the musculature forming an irregular network, which is 

 strongest on the right side. 



Viscera on the left side of the branchial sac. 



Branchial sac provided with internal longitudinal bars. Stigmata 

 straight. 



Dorsal lamina usually a plain membrane, rarely languets (Abyss- 

 ascidia). 



Ascidia, Linn. 



Only the typical genus Ascidia is represented in this collection. It 

 contains two now species. 



