304 THE SCYPHOMEDUS^E OF THE SOUTHERN HEMISPHERE, 



Thysanostoma Lessoni. L. Agassiz, 1862. Mongr. Acal. 

 Contrib. IV., p. 153. 



Umbrella semi-spherical, twice as broad as high, with 80 (?) 

 marginal flaps (in each Octant 8 rectangular flaps, the sides of which 

 coalesce. The velar flaps are truncate and lie between two elon- 

 gated ocular flaps.) Exumbrella prettily and regularly slabbed with 

 polygonal (5 or 6 cornered) slabs, which are as broad as the 

 marginal flaps. Arms several times as long as tbe diameter of 

 the Umbrella, very thin, getting gradually thinner towards the 

 pointed end. 



Colour : Umbrella whitish, with rust-coloured margin, Gonads 

 yellowish, arms dark yellowish-red. 



Size : Breadth of Umbrella, 300-400 mm. Height of Umbrella, 

 100-200 mm. 



Locality : New Guinea, Harbour of Dorey. Lesson. 



Genus. Leptobrachia. 



Crambessidse without free uppei'-arms, with ribbon-shaped, very 

 long and thin under arms, which possess suctorial crisps towai-ds the 

 distal end above the terminal knot. Mouth-cross with 4 rays with- 

 out special frills. 



Species. Leptobrachia le])toptts. 

 Haeckel, System der Medusen. Seite, 630. 



Leptobrachia leptopus. Brandt, 1838. Bulletin Acad. Petersb., 

 Tom. I., Nr. 24, p. 191. 



Leptobrachia leptopus. L. Agassiz, 1862. Monogr. Acal ( 

 Contrib., IV., p. 154. 



Rhizostoma leptopus. Chamisso et Eysenhardt, 1821. Nova, 

 Acta phys. med. n. e., Tom. X.. p. 356. Taf., 27. 



Rhizostoma leptopus. Eschscholtz, 1829 System der Acale- 

 phen, p. 52. 



