102 THE AUSTKALIAN MUSEUM. 



folds on the stomach. The usual intestinal gland opens into stomach 

 about its middle (fig. 11). 



Gonads one on each side. Ovaries only in the young Ascidiozooids 

 (fig. 6). 



Locality. Port Jackson ; about a dozen colonies. 



This species has some systems that are almost as small and as 

 circular as those of a typical Botryllus, but others again form long lines 

 (PI. Bot. L, fig. 5). 



Botrylloides leptum, variety, PI. Bot. I., figs. 1 4. 



Two colonies in the same bottle with those last described differ in a 

 few particulars, but I hesitate to form a new species for them until we 

 know more as to the range of individual variation. They measure about 

 7 cm. by 4 cm., and one is shown on PI. Bot. I., fig. 1. The Ascidio- 

 zooids are more distinctly in lines, which meet to form a network. The 

 knobs on vessels in the test are bulb-shaped (fig. 2), in place of globular 

 (figs. 7 and 8), and have the narrower distal end dark with blood cor- 

 puscles. These are very abundant round the edges of the colony. The 

 Ascidiozooids are rather darker in colour, and that is due to scattered 

 pigment masses (fig. 3) in the delicate mantle. The tentacles are in 

 some cases at least 16 in number, 4 larger with 3 smaller between each 

 pair, but some of the small ones are very minute. In other particulars 

 these colonies agree with the other specimens of Botrylloides leptum. A 

 piece of the branchial sac is shown in fig. 4. 



Sarcobotrylloides, von Drasche, 1883. 



I have placed the thicker, more fleshy colonies in this genus, but they 

 really differ very little from species of Botrylloides. There are 4 new 

 species. 



Sarcobotrylloides Jacksonianum, Herd.,- PI. Bot. II., figs. 1 8. 



Colony formed of quadrangular flattened masses rising from a narrow 

 base (fig. 1) ; of a dull brownish grey colour, lighter in some places than 

 in others ; surface smooth ; size about 5 cm., by 4 cm., by 7 mm. 



Systems vary from almost circular or short elliptical forms to long- 

 parallel lines, often branching to form a network. The systems are so 

 closely placed that very little test is left between them. The Ascidio- 

 zooids stand out as lighter brown spots on the dark grey test. The 



* See "Revision." p. 609. 



