76 THE AUSTRALIAN MUSEUM. 



Alimentary canal. The oesophagus curves round ventrally, and 

 enters the stomach on the side. The stomach is oval and lies 

 transversely (fig. 11). It has 3 or 4 longitudinal folds on each side. 

 The intestine is rather narrow, and runs first posteriorly and then widens 

 suddenly into a thick-walled heart-shaped cavity, which tapers off into 

 the intestine, which then turns anteriorly and runs up the dorsal 

 side of the thorax, nearly as far as the atrial languet. The rectum 

 is wider than the intestine, but very thin-walled, so that the faecal 

 pellets show through distinctly. 



Reproductive organs. None of the Ascidiozooids examined showed 

 any trace of reproductive organs in the post-abdomen. Vascular append- 

 ages are present, budding freely, both from the ends and sides of the 

 post-abdomen (fig. 11). 



Locality. Port Jackson ; one colony. 



Amaroucium anomalum, n. sp., PI. Pel. III., figs. 11 16. 



External appearance. The colony is small, and of nearly globular 

 form. It is attached to the side of a small sponge (PI. Pel. III., fig. 11). 

 The colony is of a light grey colour, the Ascidiozooids showing through 

 of a darker tint. The anterior ends of the Ascidiozooids are all at the 

 upper end, which is twisted over to one side. The rest of the colony is 

 smoother and more compact. The length of the colony is l - 5 cm., and 

 the breadth l - 2 cm. 



The Ascidiozooids are set at right angles to the surface, and are all 

 nearly parallel in position. The thorax and abdomen measure about 

 7 mm., and the post-abdomen about 5 mm. (fig. 14). 



The test is soft and gelatinous round the anterior ends of the Ascidio- 

 zooids. On the rest of the colony it is firm and compact. It contains 

 no bladder cells and no pigment cells, but many rather large test cells. 

 The test is traversed by vascular appendages arising from the post- 

 abdomen of the Ascidiozooids, which run almost parallel with one 

 another towards the lower end of the colony, and give off, usually alter- 

 nately, short lateral branches, which bear clumps of terminal bulbs 

 (see fig. 16). There seems to be no anastomosis between the various 

 branches. The ectoderm covering these vessels is distinctly columnar. 



The mantle is very strong and muscular. The thorax has longitudinal 

 fibres, and also transverse bands running round between the rows of 

 stigmata. The longitudinal muscle bands are strong over the post- 

 abdomen. 



The branchial sac is rather opaque. There are 9 or 10 rows of 



