PLANAXIDA. 191 
Possibly may have got mixed; it was amongst a lot of Pl. 
nicobaricus ? ‘ 
var. similis. 
Planaxis similis, Smith, Ann. Mag., XII, 1872, Sandwich Island—tong. 11}, 
diam. 54 mil. 
6 Bombay; coll. Rev. 8. B. Fairbank. 
Very variable; sometimes attains a relatively large size—viz., 
long. 164, diam. 9 mil, 
16. Planaxis nicobaricus. 
Planaxis nicobaricus, von Frauenfeld, Moll. Novara Exp. 1866, Nicobars— 
long. 12, diam. 8 mil., anfr. 6; Con. Iconica, fig. 18, as Pl. niger [not 
Pl, niger, Quoy]. 
Prof. -von Martens, Zool. Record for 1866, p. 182, says of 
this species—“ Most closely allied to Pl. nucleus [Brug.] and 
P. ovatus [Krauss ].” 
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 74 mil. 
3 New Caledonia ; ex c. P. Bouvier, Esq. 
15 Andamans and Nicobars; coll. F, A. de Roepstorff and Dr, F, 
Stoliczka, 
