66 THE AUSTRALIAN MUSEUM; 



The test is soft and spongy. It contains fusiform, spherical and 

 stellate small test cells. There are also large bladder cells, but no pig- 

 ment cells. 



The mantle is thin. The muscle bundles run longitudinally. The 

 branchial aperture is 6-lobed. 



The branchial sac is wide, and has large stigmata, which are about 

 seven times as long as they are wide. The transverse vessels are narrow. 

 There are 5 rows of stigmata, with 12 in each row. 



The dorsal lamina is represented by a series of 4 languets. These are 

 large, stout, and not tapering, but bluntly rounded. 



The tentacles are usually 12 in number, 6 large and 6 small, placed 

 alternately. 



The dorsal tubercle is simple, with an oval aperture. 



The alimentary canal crosses so as to resemble a figure of eight. The 

 stomach is placed far back, and the intestine crosses the oesophagus to 

 reach the dorsal edge of the thorax. 



The spermatic vesicles form a nearly spherical 8-lobed mass, lying 

 immediately behind the stomach, and therefore not in the intestinal loop. 

 The vas deferens arises from the centre of the mass and runs along the 

 intestine to the cloaca. 



Locality. Port Jackson and Port Stephen ; also some on a crab 

 (Macippe spinosa, Stimpson). 



There are nearly thirty specimens, many of them being united in groups 

 by the branched stolon. This species is closely related to Colella pedun- 

 cnlata, from which it differs, however, in the fact that here the peduncles 

 branch at their lower ends to form the stolon which unites several colonies 

 together in groups, and also in the number and condition of the tentacles, 

 those of C. pedunculate/, being 16 in number, and all of the same size. In 

 the present species, however, there is a good deal of variability in the 

 number and arrangement of the tentacles, partly due, no doubt, to differ- 

 ence in age and size of the Ascidiozooids. I have found 6 small similar ones, 

 8 of two sizes, 3 long and 9 very short, 10 of varying sizes, 12 alternately 

 large and small, and finally 18 or 20 large and small, with 2 or 3 of the 

 larger ones much longer than the rest. 



There are also fifteen colonies from Port Jackson, which probably 

 belong to the present species. They are all small and evidently im- 

 mature. One measures as follows : Length of body 6 mm., breadth 6 

 mm., thickness 4 mm., length of peduncle 5'5 cm., diameter 2 mm. 

 They resemble the above-described species in the external appearance, 

 in the shape and number of their stigmata, the shape of the stomach, 



