-288 STUDIES ON TUXICATA, 



The dorsal lamina (PL xxv., fig. 6) is represented by a series of 

 fairly stout languets placed rather far apart. 



The dorsal tubercle (PI. xxv., fig. 6) is circular; the aperture is 

 curved so as to include a cordate area; the arms are sharply 

 turned back but do not extend beyond the area. 



The tentacles (PI. xxv., fig. 6) are very numerous (about sixty), 

 fine filiform processes fringing the branchial aperture, not long 

 enough to meet across it. 



The genital gland is situated in the intestinal loop, and, with 

 the stomach and intestine, makes a compact visceral mass. 



The alimentary canal. — The oesophageal aperture is situated at 

 the postero-dorsal end of the sac (PL xxvii., fig. 6). The oeso- 

 phagus is short, slender and very delicate; it leads into the wide 

 flattened stomach. The wall of the stomach is thrown into 

 irregular longitudinal ridges. The intestine and rectum are not 

 defined, one from the other. The stomach and intestine lie 

 posterior to the branchial sac, slightly to the right; the intestine 

 is on the left hand side of the stomach. The rectum passes up 

 nearly to the base of the atrial siphon along the dorsal edge of 

 the body (see figs. 6-7, Plate xxvii. ). 



jjah. — Hobart Harbour; 5 fathoms (A. Morton). 



Types to be presented to the Australian Museum. 



This is apparently a fairly common species; there are altogether 

 nineteen specimens in the collection, mostly in clusters of two to 

 four; there is also one cluster made up of four specimens of this 

 species, and three of Dendrodoa gregaria Kesteven {injra). Since 

 all the specimens have been squashed and distorted, it is not 

 possible to give accurate measurements; a fairly typical example 

 which was carefully distended gave the following dimensions. 

 Length exclusive of siphons 2, breadth (dorso-ventral) 2-5, thick- 

 ness (lateral) 1 -5 cm. 



The novelty is distinguished from the other members of its 

 genus by the lobation of the siphons, and the situation of the 

 viscera. Since both these characters necessitate a modification 

 of the generic description, the question arose as to whether it 



