100 TETHYS-AUSTRALASIAN. 



Aplysia norfolkensis SOWB., Conch. Icon., pi. 10, f. 42a, b (Aug., 

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



The auricle produced by the reflected dorsal margin is more ex- 

 panded in Aplysia coneava than in this similarly shaped but differ- 

 ently colored shell. (Sowb.~) 



T. CONCAVA Sowerby. PI. 43, fig. 27 (enlarged). 



Shell small, straw-colored, thin, ventricose, transverse, smooth, 

 white within ; apex small, rounded, strongly incurved, subauricu- 

 lated on both sides, upper side concave, short ; dorsal margin re- 

 flected, elevated, oblique, sloped towards the outer lip. (Sowb.~) 



Australia (Sowb.). 



Aplysia coneava SOWB., Genera of Shells, fig. 3. A. coneava 

 SOWB., Conch. Icon., pi. 6, f. 24a, b. 



Aplysia anguilla is more transverse, and Aplysia rosea more tri- 

 angular than this species, although they nearly resemble it ; the 

 apex is auriculated, and the reflected lateral margins near it 

 (Sowb.) 



Much like elongata Pse., norfolkensis Sowb., and parvula Guild. 

 I suspect it to be identical with one of the latter species, notwith- 

 standing the locality given by Sowerby. The original figure meas- 

 ures 9? mill long. 



T. EXCAVATA Sowerby. PI. 58, figs. 32, 33. 



Shell pale, thin, subquadrate, scarcely oblong, concentrically 

 striped, ventricose, within thinly testaceous, apex not prominent, 

 thin, roundly incurved ; upper margin short, scarcely excavated, 

 square at the end, outer lip rather straight ; lower margin square ; 

 dorsal margin very thin, convex. (Sowb.~) 



Port Jaekson (Angas), 



Aplysia excavata SOWB., Conch. Icon., xvii, pi. 3, f. 8a, b (Aug., 

 1869). ANGAS, P. Z. S., 1877, p. 190. Aplysia hyalina SOWB., t. 

 c., pi. 4, f. 13a, b, ANGAS, I. c. 



Aplysia excavata and hyalina were described from shells only, and 

 these are so similar that I believe them to belong to one species. 

 The description of hyalina is a follows : 



Aplysia hyalina (pi. 58, figs. 30, 31). Shell round, pellucid, hya- 

 line, ventricose, thinly concentrically ridged ; back convex, with a 

 sulcus near the margin ; apex depressed, rounded, incurved ; upper 

 margin elevated, rounded at the end ; outer lip convex ; dorsal mar- 



