CATALOGUE OF TUNICATA. 25 



the siphon, where the invaginated test becomes very thin and mem- 

 branous, it bears scattered simple finger-like tentacles of moderate size 

 (fig. 4, in.). These, of course, are supplementary to, and are placed 

 anterior to the usual circle of much larger compound tentacles at the 

 entrance to the branchial sac. 



Microcosmus affinis, Heller, PL Cyn. VI., figs. 68. 



This species was briefly described by Heller in 1878. In the present 

 collection there are half-a-dozen specimens which I refer to the species, 

 and as Heller gave only a figure of the exterior, I think it right to re- 

 describe and re-figure it. Three of our specimens are united in a clump, 

 the other three are separate. The exterior agrees well enough with 

 Heller's description, and fig. 6 shows the characters. Our largest 

 specimen measures 3 cm. by 2-5 cm. by 1 cm. The invaginated test of the 

 branchial siphon shows 4 slight semilunar valves near the base of the 

 tube. The branchial sac has usually a 9th slighter fold next the endostyle 

 on one or both sides which does not extend to the posterior end of the 

 sac. There are 8 bars on a fold and 2 in the interspace. The stigmata are 

 rather short, wide and rounded. There are about 6 in the larger meshes. 

 Every 7th or 8th transverse vessel is much wider than those between 

 (see fig. 7). 



The tentacles are of two sizes, about 9 of each, the larger ones are 

 very bushy. The dorsal lamina is a plain membrane. The dorsal tubercle 

 is broadly cordate, with both horns spirally coiled inwards (fig. 8). 



This form not only resembles M. clauclicans, Savigny, as pointed out by 

 Heller, but also very closely agrees with Heller's other species, Micro- 

 cosmus distans, which was found at New South Wales. I strongly 

 suspect they are all one species. It is also allied to the new species, 

 M. Raiusayi. 



Microcosmus Ramsayi, :;: n. sp., PL Cyn. VI., figs. 15. 



External appearance. Shape irregularly ovate, somewhat compressed, 

 attached by the posterior end. Apertures moderately far apart, usually 

 prominent, and anterior, both 4-lobed. Surface folded and wrinkled. 

 Colour dull yellowish brown. Size 5 cm. in length, 3'5 cm. in breadth, 

 and 2 cm. in thickness. 



Test tough and leathery; rather thin over most of body, thickest 

 round apertures. 



* I have named this characteristic Australian .species after Dr. E. 1'. Ramsay, who 

 was Curator of the Museum at the time the collection was .scut to inc. 



