332 STUDIES ON AUSTRALIAN MOLLUSCA, xi., 



one of these, an inch broad, an inch and a half long, my figure is 

 derived. Mr. J. C. Gabriel is responsible for including this as an 

 Australian species. My figure does not well agree with the shell to 

 which he referred. 



Cassidula dkcussata H. & A. Adams. 

 (Plate xix., figs. 82,83.) 



Cassidula decussata H.& A. Adams, Proc. Zool. Soc.,1854(1855), 

 p. 32. 



This Australian species has not been previously figured. The 

 present drawing is of one in a lot of three, in the British Museum, 

 marked types. It is in length 12 mm., in breadth, 7 mm., and 

 labelled "Cassidula decussata H. & A. Ad., P.Z.S., 1854, p. 32, 

 Hab., Moreton Bay, M.C." 



Cassidula sowerbyana Pfeiffer* has been confused both with C. 

 decussata and C. doliolum. But, on assembling these notes, I find 

 that I failed to observe their differential characters. 



Cassidula doliolum Petit. 

 (Plate xix., fig. 84.) 

 Auricula doliolum Petit, Proc. Zool. Soc, 1842, p. 201. 

 Cassidula doliolum Pfeiffer, Cat. Auricul. in Brit. Mas., 1857, p. 

 83. 



In the British Museum are three, perhaps types, but not so 

 marked, labelled, "doliolum Petit, M.C." These are 9 mm. long, 

 and 6 mm. broad. One of them is here represented. 



An unnamed form of the same species is only marked "Aus- 

 tralia." It is larger, viz., 13 mm. long, and 7 mm. broad, and has 

 the colouring of C. sonata, from which a mucronate apex and four 

 alternately larger and smaller denticles within the outer lip, dis- 

 tinguish it. 



Leuconopsis pellucidus Cooper. 

 (Plate xix., fig. 85.) 

 Auricula pellucida Daniel Cooper, Microscopic Journ. i., Jan. 

 1841, p. 16; Id., Pfeiffer, Cat. Auric. Brit. Mus., 1857, p. 109; Id.. 



* Tapparone-Canefri, Ann. Mus. Genoa, xix., 1883, p. 227, text -fig; and 

 von Martens, Weber's Zool. Ergebnisse, iv., 1897, p. 147, PI. viii., fig. 3. 



