MONODONTA. 



marked with a few spiral subimpressed lines which are sometimes 

 obsolete, leaving the surface smooth ; color plumbeous ashen, often 

 with a pink tinge, speckled closely with white dots, and encircled 

 witli two dark bands which are articulated with larger spots of white; 

 sutures impressed ; whorls 5, subconvex, the last forming the greater 

 portion of the shell, compressed, obtusely angulated, depressed below 

 the suture, the surface of the base almost entirely occupied by the 

 parieto-columellar area ; aperture very oblique, pearly, iridescent 

 inside ; outer lip acute, thin, continued on the base in an angle which 

 bounds the columellar area ; columella subhorizontal, thin, very wide, 

 subconcave, white, bounded by a narrow brown streak outside. 



Alt. <, diuin. 10 mill. 



JYetu Caledonian Archipelago. 



T. comtellatus SOUVERBIE, Journ. de Conch., 1863, p. 279, t. 12, f. 

 3. FISHER, Coq. Viv., p. 271, t. 90, f. 1. 



A very depressed, almost Trochita-shaped species. There is con- 

 siderable variation in the color-pattern. Unlike most of the preced- 

 ing species, the base is not lined with a white thickened continuation 

 of the columella. 



M. EXCAVATA Adams et Angus. PI. 35, figs. 1, 2, 3. 



Shell small, imperforate, depressed-conic, oblique, light green, 

 closely maculated and mottled in minute pattern with dark olive, the 

 markings sometimes assuming the form of obliquely descending dark 

 bars; spire conoidal, the apex eroded, whitish; the penultimate 

 whorl quite convex, ruddy or purplish ; suture well impressed ; 

 whorls 4, the last conic above, flattened beneath, carinate at the 

 periphery ; almost the entire surface of the base occupied by the 

 large, very oblique aperture ; outer lip acute, arcuate, not thickened 

 within, inside brilliantly iridescent, smooth or nearly so; columella 

 subhorizontal, its edge arcuate, thin, acute, extending below upon 

 the base, forming a ledge within the basal lip; parieto-columellar 

 area very large, eroded, concave, white. Alt. 5, diam. 6 mill. 



New Zealand. 



Trochocochlea excavata AD. and ANG., P. Z. S., 1864, p. 37. 

 HUTTOX, Manual X. Z. Moll., p. 97. 



A species allied to M. constellata, but smaller, lacking dark Spiral 

 bands, more angular at the periphery, more concave beneath, and 

 with the columella prolonged in a distinct ledge within the basal lip. 

 To M. perplexa it is also related ; but is smaller, more angulated, 



