CATALOGUE OF TUNICATA. 85 



Psammaplidium, Herdman, 1886. 



This includes those species where a great part of the bulk of the 

 test is made up of imbedded and encrusting sand grains. Nine species 

 were previously known, and this collection has added 5 more. 



Psammaplidium solidum, Herdman,* PL Pel. V., figs. 15. 



Colony rather massive, formed of thick lumps, with few lobes, 

 scarcely branched (fig. 1). No visible place of attachment. Ends of 

 Ascidiozooids visible on the surface, closely crowded together. No 

 common cloacal apertures seen. Closely covered with encrusting and 

 imbedded sand grains. Surface rather smooth and glistening in parts. 

 Colour a grey sand tint. Length about 8 cm., breadth 4-5 cm., thickness 

 1 cm. 



Test thickly encrusted with sand grains and other foreign particles, 

 which penetrate into the centre of the colony. Outer layer rather 

 tougher than the rest, so as to form a membrane. No bladder cells, 

 pigment cells or vessels visible in test ; test cells small and not very 

 numerous (fig. 2). 



Ascidiozooids placed at right angles to the surface, small. The 

 thorax is about 0'7 mm. long, and the post-abdomen is very short (fig. 3). 

 The branchial aperture is distinctly 6-lobed. 



The mantle has the majority of the muscle fibres running longitudi- 

 nally ; there are a few transverse bundles on the thorax. Atrial languet 

 either very small or absent. 



The branchial sac has both transverse and inter-stigmatic vessels 

 very narrow (fig. 5), and the stigmata remarkably wide, the width being 

 nearly half their length. 



Tentacles about 12 in number, short and stout (fig. 4). 



Endostyle thrown into a series of close lateral undulations (fig 3). 



Alimentary canal with a long, narrow- oesophagus, and a stomach 

 with about 6 longitudinal ridges, intestine thick-walled, rectum thinner, 

 with oval black pellets of faecal matter. 



Gonads in short post-abdomen, just below loop of intestine. Both 

 spermatic vesicles and well-developed ova were present, and there were 

 large tailed larvae in the peribranchial cavity. 



Locality. Port Jackson ; one colony. 



Psammaplidium lobatum, Herdman, f PI. Pel. V., figs 6 12. 

 Colony large, irregularly-lobed, slightly branched, and erect, the 



* ".Revision," 1891, p. 620. 

 t "Revision," 1891, p. 6?0. 



