MONODONTA. o7 



blackish ; spire conic, acute ; whorls 6-7, slightly convex, spirally 

 sculptured with coarse, irregular, coarsely granose lime, about 6 in 

 number on the penultimate whorl ; sutures not much impressed, the 

 whorl flattened just below it; last whorl globose, rounded; base 

 rounded ; aperture oblique lined with a white porcellaneous layer, 

 rounded, the outer and basal lips margined with green, beveled to 

 an edge, plicate within ; columella short, projecting and terminating 

 as a square tooth-like prominence into the aperture below, forming a 

 square notch between it and the oblique plications of the base ; 

 parietal wall not calloused above. Alt. 35-40, diam. 28-34 mill. 



Indian Ocean; E. African Coasts; E. Indies; Japanese and Chi- 

 nese Seas. 



An abundant and mutable species, very variable in the compar- 

 ative length of the spire, and in coloration. 



Trochus lafyio LINN, Syst. Nat. x, p. 759 (1758). Monodonta 

 labio LA.MARCK, Encyc. Meth., p. 447, f. 1, 2 and of. other authors. 

 -Trochus labio PHILIPPI, Conchyl. Cab., p. 166, t. 27, f. 1-4, t. 44, 

 f. 8. FISCHER, Coq. Viv., p. 223, t. 73, f. 1, t. 74, f. 4. Monodonta 

 confusa, TAP-CAN., Zool. Viaggio della Magenta, Malac., p. 61, t. 1, 

 f. 8 (1874). 



TroschePs figure of the dentition of this species is given on PI. 50, 

 fig. 5. 



Var. CONFUSA Tapparone-Canefri. PI. 22, fig. 37. 



This form, of which typical examples are before me, is shaped like 

 M. labio ; the color is pink, longitudinally clouded with dusky ; the 

 penultimate whorl bears 5 or 6, the last 13 or 14 spiral ridges ; the 

 second one from the suture is very narrow ; the others are subequal, 

 but become smaller beneath ; there are no lirulse intercalated 

 between the ridges on the last whorl, as is usually the case in M. 

 labio ; and the ridges are very conspicuously and regularly cut into 

 oblong subquadrangular or lozenge-shaped grains by vertical iinpres-: 

 sions as deep as the inter-liral grooves ; the basal tooth of the col- 

 umella is smaller and more acute than in typical M. labio. 



Alt. 16, diam. 15 ; alt. 20, diam. 18 mill. 



Singapore. 



Var. minor, or immanis of Fischer (1880) seems to be identical 

 with confusa. 



Tapparone-Canefri's figure, copied on my plate, does not distinctly 

 enough show the coarsely granose character of the lira?. 



The figure 88 of plate 62 represents, according to Philippi an 

 aberrant form of M. labio. 



