TETHYS-AUSTRALASIAN. 101 



gin convex, reflected ; lower margin round. A beautifully trans- 

 parent, rounded, ventricose shell, much differing from other known 

 species. (Sowb.) 



Port Jackson, at Lane Cove (Brazier). 



T. SYDNEYENSIS Sowerby. PL 57, figs. 22, 23. 



Shell compressed, perpendicularly oblong, chestnut in the middle, 

 pale horn near the margins ; apex obtuse, terminal, reflected, in- 

 curved ; upper margin straight ; outer lip straight ; lower margin 

 subquadrate ; dorsal margin convex. (Sowb.~) 



Shark Island, Port Jackson (Brazier). 



Aplysia sydneyensis SOWB., Conch. Icon., pi. 7, f. 31a, b (August, 

 1869). ANGAS, P. Z. S., 1877, p. 190. 



The shell of this species has some resemblance to that of a Pleu- 

 robranchus. (Sowb.*). 



Considerably like T. excavata, but narrower. 



T. ANGASI Sowerby. PL 57, figs. 18, 19. 



Shell compressed, thin, smooth, subtrigonal, arched, pale brown, 

 very slightly testaceous, concentrically striped towards the apex ; 

 apex elevated acuminated, cuneate ; outer lip produced below ; dor- 

 sal margin convex, sloped towards the ventral margin. (Sowb.) 



" Sow and Pigs " Reef, Port Jackson (Brazier). 



Aplysia angasi SOWB., Conch. Icon., xvii, pi. 8, f. 35a, b. ANGAS, 

 P. Z. S., 1877, p. 190. Aplysia keraudreni SOWB., Conch. Icon., pi. 

 1, f. 2a, b.Syphonota keraudreni ANGAS, P. Z. S., 1867, p. 228. 

 Not A. keraudrenii Rang, 1828. 



Flatter than the shell of Aplysia depilans, which it much resem- 

 bles. It is thinner at the edges, and the apex is not at all callous, 

 but pointed and incurved. The dorsal margin is more rounded. 

 (Sowb.) 



With A. angasi I am disposed to unite A. keraudreni of Sow- 

 erby's Monograph, which differs markedly from the keraudrenii of 

 Rang in the shorter sinus, etc. 



T. SOWERBYI Pilsbry, n. n. PL 57, figs. 20, 21. 



Animal olive, mottled with black. Shell internal, thin, horn 

 color, oblong, produced and curved at the apex. Length 1 inch, 

 3 lines, breadth 1 lines. ( Angas.} 



Shell oblong, thin, subtrigonal, pale, oblique, hatchet-shaped, 

 arched, tumid, sinuously striped near the umbones, within thin ly tes- 



