CATALOGUE OF TUNICATA. 43 



Mantle pale yellow, thin, not very muscular. 



Branchial sac soft, with 4 well-marked folds on each side. There are 

 6 internal longitudinal bars on the fold and 3 in the interspace. There 

 are 3 or 6 narrower transverse vessels between each pair of wider ones. 

 The stigmata are slender and regular, and about 10 or 12 in each of the 

 elongated meshes. 



Tentacles numerous, long, closely placed ; all much of same length. 



Dorsal tubercle simple, cordate in form, but with the 2 horns turned 

 symmetrically out. 



Locality. Moreton Bay ; one specimen. 



The notable feature about this species is the remarkable bunch of root- 

 like or stolon-like processes from the posterior end (PL Cyn. XV., 

 fig. 8). There are about 20 of these, and most of them are simple and 

 finger-like in shape ; a few, however, divide, and here and there are 

 placed knob-like thickenings. The surface test of the processes and 

 knobs is slightly sandy, and bears minute processes or villi. The mantle 

 at its posterior end is prolonged into several tubes in the test (fig. 9), and 

 these prolongations split to supply the processes. The knobs contain 

 enlargements of the mantle, but apparently nothing else. 



The mantle has its musculature in the form of a minute network of 

 interlacing fibres, so as to form a fine felting. 



The occasional larger transverse vessels of the branchial sac are very 

 much wider than those between (fig. 11). The longitudinal bars are 

 rather stout. Figure 10 shows the symmetrical dorsal tubercle. 



The gonads form 4 or 5 elongated masses, converging to the atrial 

 aperture. 



Polycarpa, Heller, 1877. 



This is the genus that contains the largest number of species in the 

 present collection. There are 12, of which 6 are new to science. Some 

 of the species of Polycarpa come very close to Styela, and it is quite a 

 question whether these genera will ultimately remain separate. 



Polycarpa fungiformis, n. sp., PI. Cyn. XVI., figs. 1 10. 

 External appearance. Body irregularly globular, and placed on the 

 end of a long stalk, which is rooted by a spreading lower end. Apertures 

 both on the upper end, distant, minute, inconspicuous. Surface even, 

 and fairly smooth. Colour quite black. Greatest extent of body, which 

 is dorso-ventral, 3'5 cm. ; breadth, antero-posteriorly, 2-5 cm. Length of 

 stalk 5' 5 cm., thickness from about 3 mm. to 8 mm. 



