78 THE AUSTRALIAN MUSEUM. 



attachment (PI. Pel. 1, fig. 5). The widest part is about the middle of 

 the Ascidiarium. There is no marked line of demarcation at the top 

 of the peduncle. The colour is light yellowish grey all over, except close 

 to the point of attachment, where it is a little darker. The dimensions 

 of the larger colony are : Length of Ascidiarium 6 cm., breadth 4'7 cm., 

 thickness 4 - 5 cm. Length of peduncle 4 cm., thickness 2-5 cm., tapering 

 down to 1'3 cm. 



The Ascidiozooids are scattered irregularly. They are large, being 1-5 

 cm. in length and l - 5 mm. in breadth. The thorax is only half as long 

 as the long, narrow abdomen (fig. 6). They are all retracted, so as to lie 

 deeply in the test, and in some the thorax is much contracted. The long 

 bodies of the Ascidiozooids penetrate the test in all directions. 



The test contains many bladder cells and large test cells. There are 

 no pigment cells. 



The mantle is strong over the thorax. It is provided with longi- 

 tudinal muscle bands running with regularity down the thorax and 

 bifurcating at the base of the branchial siphon. The apertures are 

 6-lobed. An incubatory pouch is present, but no tailed larvae were seen. 



The branchial sac has about 10 rows of stigmata, with 15 in each row. 

 The stigmata are about 8 times as long as wide. Narrow horizontal 

 membranes are present, running along the transverse vessels (fig. 7). 



The dorsal lamina is represented by a long series of closely-placed, 

 rather small languets (fig. 8). 



The tentacles are 14 in number and of 2 sizes, placed alternately. The 

 larger ones are not all of the same size, and one of them, (placed laterally) 

 is much larger than the rest. 



The dorsal tubercle has a simple circular opening. 



The alimentary canal forms a very long and narrow loop, rather wider 

 posteriorly than where it joins the thorax (fig. 6). The oesophagus and 

 intestine are both very long and straight. The ovate stomach is placed 

 posteriorly. 



The reproductive organs are placed in the intestinal loop, the spermatic 

 vesicles being posterior to the ovary. The spermatic vesicles are 

 arranged in grape-like clusters. They are small and numerous, while the 

 ova are few and large. In the younger Ascidiozooids the ova are rather 

 more numerous and the spermatic vesicles fewer and smaller. It is 

 evident that the Ascidiozooids are protogynous. 



Locality. Port Jackson ; two specimens. The second is only about 

 half the size of the one measured. 



