CATALOGUE OF TUNICA.TA. 23 



Cynthia, or rather, on account of the numerous spicules, in my genus 

 Rliabdocynthia. But all the other characters agree so closely with 

 those of species of Microcosmus, and the animal seems so closely related 

 to M. Julinii, v. Dr., that I am inclined to think that what is at fault is 

 our present definition of the genus Microcosmus, and that we shall have 

 to admit within its limits either dorsal lamina or dorsal languets, as we 

 have had to do in Cynthia. Consequently, I consider that I am placing 

 the present form nearest to its natural allies in calling it a Microcosmus. 

 I regard it as closely related to M. Julinii, v. Dr. , which was brought by 

 the " Novara " Expedition from Sydney. In fact, there are some points, 

 such as the remarkable dorsal tubercle, in which it entirely agrees with 

 that species, and at first I thought I had specimens of M. Julinii before 

 me, but the presence of the languets renders that identification impossible, 

 as von Drasche's species has a smooth edged dorsal lamina. 



There are some points of resemblance between the present species 

 and Rhabdocynthid complanata, Herdm., which was found by the 

 " Challenger " Expedition at Port Jackson. The spicules and their 

 arrangement are remarkably alike. The dorsal tubercle of R. complanata 

 looks as if it might be a young form of that of the present species. 



If Microcosmus draschii is ever moved to the genus Rliabdocynthia, its 

 place will be beside R. complanata, and M. Julinii will have to accom- 

 pany it. 



Microcosmus australis, n. sp., PI. Cyn. V. 



External appearance. Shape erect oblong with the branchial aperture at 

 the anterior end and the atrial one-third down the dorsal edge. Attached 

 by the posterior end, scarcely compressed from side to side. Apertures 

 both prominent, but small. Surface much wrinkled and roughened. 

 Colour tawny yellow. Size about 3 cm. by 2-5 cm. by 1-5 cm. 



Test thin, but tough; white on inner surface; its prolongation into 

 the branchial siphon bearing minute spines in its outer part, and simple 

 tentacles in its inner part. 



Mantle opaque yellow, muscular, with circular bands outside and 

 radial inside. 



Branchial sac with 8 to 10 folds on each side. Several of those next 

 the endostyle slight. There are about 6 or 7 internal longitudinal bars 

 on each fold and about 3 to 5 in the space between. Every 6th or 7th 

 transverse vessel is much wider than the intervening ones, sometimes 

 every third one is a little wider. The meshes contain about 6 stigmata 

 each, occasionally as many as 10 or 12. 



Dorsal lamina a plain membrane with a smooth edge. 



