68 THE AUSTRALIAN MUSEUM. 



india-rubber. On account of the contraction of the Ascidiozooids there 

 are large spaces left in the test (see fig. 4) which were occupied by the 

 thoracic regions when in the expanded state. The structureless matrix 

 contains spherical and ellipsoidal large cells, and smaller stellate and 

 and spherical test cells, and also yellow pigment cells (figs. 5 and G). 



The mantle has muscle bands running longitudinally, and also a few 

 regularly placed transverse bands. An incubatory pouch is present on 

 the dorsal edge. 



The branchial sac has 6 or 7 rows of stigmata (fig. 10), which are 

 closely placed. The stigmata are from five to seven times as long as 

 broad (figs. 11 and 12). The transverse vessels are narrow. 



The dorsal lamina is represented by long, narrow, almost tentacular 

 languets (fig. 13). 



The tentacles are 30 in number, and consist of 5 very long, 10 

 medium sized, and 15 very short, placed with regularity as follows : 

 long, short, medium, short, long. The short tentacles spring from a 

 level further posteriorly than the line of insertion of the others. 



The dorsal tubercle has a simple circular aperture leading into a 

 long, narrow funnel shaped cavity. 



The alimentary canal is long and narrow in the younger Ascidiozooids 

 at the base of the colony (fig. 7), but becomes much shorter as the 

 reproductive elements are shed, and the Ascidiozooid is pushed up 

 nearer to the top (figs. 8 and 9). The lining of the stomach and 

 intestine are thrown into numerous folds. 



The reproductive organs, both male and female, are placed in the 

 intestinal loops of the young Ascidiozooids. Embryos in various stages 

 of development are seen in the incubatory pouches of the older 

 Ascidiozooids (fig. 8). 



Locality. Port Jackson. 



There are about 30 colonies of this species, but of these 15 smaller 

 ones are united into one mass by the branching rootlets given off by the 

 lower ends of their peduncles. Other 4 larger colonies are similarly 

 united, as shown in fig. 1. The Ascidiozooids differ considerably in 

 shape and size in different parts (figs. 7 10). Near the top of the 

 peduncle Ascidiozooids are found with a long-looped alimentary canal, 

 and reproductive organs in the loop, while at the top of the colony 

 are found Ascidiozooids having short-looped intestines, and provided 

 with incubatory pouches. The stolon - like appendages from the 

 Ascidiozooids are shown in figs. 14 and 15. 



This species is evidently very abundant on some parts of the Austra- 



