20 THE AUSTRALIAN MUSEUM. 



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Branchial sac with more than 4 folds upon each side (except Forbesella 

 tessellata, Forbes). 



Tentacles compound. 



Alimentary canal with no marked stomach, but with a glandular lobed 

 appendage. 



Of the four described genera of this sub-family, the two commoner 

 ones, Cynthia and Microcosmus, are well represented. 



Microcosmus, Heller 1877. 



This genus is distinguished (see Heller, and " Eevision," p. 573) from 

 Cynthia by the narrow intestinal loop and the plain dorsal lamina. 

 Several species were previously known from Australian seas, and three 

 new ones have been added by the present collection. 



Microcosmus Draschii, Herdman,* (1891), PI. Cyn. Ill and IV. 



External appearance. Shape irregularly ovate or reniform, flattened 

 from side to side, attached by a variable extent of the posterior end. 

 Apertures both on the anterior end, large, on prominent knobs, distinctly 

 4-lobed. Surface very irregular, often grown over with other animals, 

 usually corrugated and crinkled. Colour from pale yellow to dark brown. 

 Size up to 16 by 12, by 6 cm. thick. 



Test leathery or pergamentaceous, rough and irregular on the outside, 

 smooth, glistening, and white or pearly on the inside. The posterior 

 part may be greatly thickened, and is then soft and spongy. 



Mantle very thick, opaque, muscular, and densely crowded with 

 calcareous spicules. The large siphons have very strong sphincter 

 muscles. 



Branchial sac large and much folded. There are from 12 to 15 folds 

 on each side. About a dozen internal longitudinal bars on a fold, and 

 four in the interspace. Meshes small, nearly square, containing 2 or 3 

 stigmata only. The larger vessels contain large fusiform echiiiated 

 calcareous spicules, and smaller ones are present in the finer vessels. 



Dorsal lamina represented by a row of small pointed languets. 



Tentacles large and branched, of 2 sizes, 12 larger and 12 shorter, 

 placed alternately. 



Dorsal tubercle very large, of circular form, with a very elaborately 

 curved pattern all over its surface. 



Alimentary canal large, forming a narrow loop along the posterior 

 edge of the left side. 



* Brit-fly diagnosed in " Revision," p. 575 ; now fully described and figured. 



