MONODONTA. 91 



Australian Coasts, Port Jackson ; York Peninsula ; Tasmania ; 

 £ass sts. 



M. constrida Lam. An. s. Vert, vii, p. 36. — T. constrictus Phil- 

 ippi, Conchyl. Cab., p. 159, t. 26, f. 2b, 3. — QuoY et Gaim., Voy. 

 de VAstrol. iii, p. 251, t. 63, f. 23, 24.— Fischer, Coq. Viv., p. 178, 

 t. 59, f. 2, t. 60, f. 4. — Trochus cochlea Wood, Lid. Test, suppl., t. 5, 

 f. 24. 



The present form may be distinguished from the following by the 

 prominence of the spiral ridges, and their number — three on the 

 penultimate, seven on the last whorl. The ridges ai-e sometimes 

 less prominent upon old specimens. 



M. ZEBRA Menke. PI. 20, figs. 20. 



Shell imperforate, thick, solid, lusterless, whitish or covered with 

 a thin greenish-yellow cuticle, conspicuously longitudinally striped 

 ivith black or dull red, the stripes sometimes zigzag ; spire conic, 

 acute ; whorls 6 to 7, convex, obliquely striated and spirally ridged, 

 the ridges 4 or 5 in number on the jDenultimate, 8 to 12 on the last 

 whorl, not so prominent as in M. constricta, and closer, especially 

 upon the base ; aperture as in M. constricta ; outer lip lirate or 

 smooth within ; columella bearing an inconspicuous blunt tubercle 

 near the base. Alt. 34, diam. 25 ; alt. 25, diam. 22 mill. 



S. Australian Coasts; Tasmania. 



Monodonta zebra Menke, Verz. Malsb. Conch. Samml., p. 17 

 {18 ). — Trochus zebra Philippi, Conchyl. Cab., p. 160, t. 26, f 4. 

 —Fischer, Coq. Viv., p. 182, t. 60, f. 2 (not T. zebra Wood).— T. 

 tceniatus Quoy et Gaim., Voy. de I' Astrolabe iii, p. 249, t. 69, f 15 

 -17 (not T. tceniatus Wood). — Trochocochlea niulticarinata Chenu, 

 Man. de Conchyl., ii, p. 360, f 2676. — Fischer, Coq. Viv., p. 184, t. 

 60, f. 3. — T. constrictus Philippi (in part) Conchyl. Cab., t. 26, f 

 2a.— Q. ET G. (in part) Voy. de UAstrol. t. 63, f. 26, 27.— T. 

 obtusus "Chemn." Philippi, Canchyl. Cab., p. 19, t. 4, f 3, 4. 



This species may be separated from the preceding by the more 

 numerous, less salient spiral ridges, and by the color pattern of dull 

 red or black stripes alternating with white. The cuticle is usually 

 rubbed off in adults, causing the underlying white to replace the 

 yellow, and intense black the red, of fresh shells. The T. multicarin- 

 utus of Chenu (pi. 20, fig. 12) differs in the much closer, narrower 

 stripes ; but that it is the merest color-variety is proven by numerous 

 intermediate specimens before me. 



