PLANAXID^. 191 



Possibly may have got mixed ; it was amongst a lot of FL 



nicobaricus ? 



var. similis. 



Planaxis similis, Smith, Ann. Mag., XII, 1672, Sandwich Island — long. 11\, 

 diam. 5? mil. 



6 Bombay ; coll. Rev. S. B. Fairbank. 



Very variable ; sometimes attains a relatively large size — viz., 

 long. 16J, diam. 9 mil. 



16. Planaxis nicobaricus. 



Planaxis nicobaricus, von Frauenfeld, Moll. Novara Exp. 1866, Nicobars — 

 long. 12, diam. 8 mil., dnfr. 6 ; Con, Iconica, Jig. 13, as PL niger [not 

 Fl. niger, Quoy]. 



Prof, von Martens, Zool. Record for 1866, p. 182, says of 

 this species — " Most closely allied to PI. nucleus [Brug.] and 

 JP. ovatus [Kranss]." 



There seems to be considerable confusion about this form. 

 Sowerby figures it excellently as above, but confused it with a 

 species of Quoy's not half its size, and consisting of four whorls 

 only. Von Frauenfeld's description and figure do not at all 

 well represent the species. I imagine they were taken from a 

 dead and worn specimen, in bad condition. 



Whorls either six or seven, the upper ones perfectly smooth and 

 of lighter colour, the last two under the lens obsoletely striate, 

 the last of all so much as to be almost smooth, except for an 

 incised infrasutural girdle, and some five or six broad sulcations 

 quite at the base. A good characteristic is the unusually sharp 

 pointed apex. The shell varies from a rich chocolate colour to 

 black and is covered with a rather thick, compact, lighter 

 coloured epidermis. The aperture is remarkably expanded or 

 " patulous," of a uniform rich brown colour, not margined at 

 peristome, denticulations within so fine as to be often almost 

 imperceptible even with a lens. 



Long. 12 to 14, diam. 7 to 7^ mil. 



3 New Caledonia ; ex c. P. Bouvier, Esq. 

 15 Andamans and Nicobars j coll. F. A. dc Roepstorff and Dr. F. 

 Stoliczka. 



