SCUTUS. 



289 



Var. australis Q. & G., (pi. 40, fig. 3.) Shell proportionately 

 broader. 



Patella unguis Schum., part (not Linn.), Syst. Vers Test. t. 22, f. 

 a-b. — Parmophorus australis Q. & G., Voy. Astrol. t. 69, f. 1-4. — 

 Scutus elongatus A. Ad. in Sowb., Thes. t. 249, f. 10. — Sowb., 

 Conch. Icon. f. Id. — S. unguis Sowb., (not Linn.) Conch. Icon. f. 

 5b. 



In some of the specimens before me the side-margins are decidedly 

 arcuate like the form called convexus Q. & G. 



This species may be distinguished from S. ambiguus by its longer 

 form and more rounded anterior end : from S. unguis by its lacking 

 the corrugation of the surface characteristic of that species, and in 

 having the apex more posterior. 



S. ambiguus Chemnitz. PL 40, figs. 9, 10, 11. 



Shell shorter than S. anatinus, the front margin squarely trunc- 

 ated. Length about twice the breadth. 



Length 54, breadth 28 mill. 



Neiv Zealand. 



Patella ambigua Chemn. Conch. Cab. xi, pp. 178, 181, f. 1918. — 

 Wood, Index Test., t. 38, f. 84. — Scutus ambiguus Ch., Smith, 

 Quart. Journ. Conch, ii, 1879, p. 258, figs. 1-3. — S. antipodes Montf. 

 Conch. Syst. ii, p. 58, 59. — Parmophorus breviculus Blainv. Bull. 

 Sci. Soc. Philom. 1817, p. 28 ; Diet. Sci. Nat. xxxvii, p. 558. — Lam. 

 An. s. Vert. ed. 2, vii, p. 579. — S. unguis H. & A. Ad. (not Linn.) 

 Genera, iii, t. 51, f. 10a. 



Fig. 11 is a dorsal view of animal showing the anterior position 

 of the shell ; fig. 10 represents Blainville's type specimen of P.. 

 breviculus ; fig. 9, a larger specimen. 



S. unguis Linne. PI. 40, figs. 4, 5, 6, 7, 8. 



Shell oblong, depressed, slightly narrowing in front or parallel- 

 sided ; apex usually between the posterior third and the middle ; 

 ends rounded, the front emarginate more or less. Surface concen- 

 trically wavy-striate and obliquely corrugated. Color buff or white. 

 Inside white or with bluish zones; muscle-scar not very distinct; 

 no punctures at the apex of the cavity. 



Length 33, breadth 18, alt. 7 mill. 



Length 54, breadth 28, alt. 8 mill. 



Length 28, breadth 15, alt. 7 mill. 



Port Essington and Moreton Bay, Australia; New Ireland; Xew 

 Caledonia; Hong Kong, China; Japan; Cape of Good Hope to 

 Bed Sea ; Bombay; Philippines. 19 



