COLLECTED IN DUTCH NEW GUINEA. 



293 



periostracum and a large rounded aperture, subperforate and with a non-reflejced 

 columella. 



Systematic Position. — The character of the foot, dorsal lobes, and genitalia enable 

 lis to place this genus among the Zonitidse, but it is difficult to decide its precise place 

 within that family. The characters here described do not associate it with any of the 

 subdivisions of the Zonitidse hitherto established. A more complete comprehension 

 of the limits and subdivisions of this family is, as a matter of fact, required ; and when 

 this is attained, the interesting form here described will no doubt be assigned a 

 satisfactory systematic position. 



Cheonos sublimis, sp. n. 

 A. External Appearance. 

 The mantle (alcohol specimens) is colourless, save for a tract of dark brown or 

 blackish grey over the region occupied by the kidney and dark irregular freckles 

 round the mantle-ediie and along the course of the rectum (PI. XXXII. fig. 9). 



The apical whorls of the body are very dark bluish black, except on their underside, 

 which is dirty yellow. The foot is dark blue to black dorsally, but on the peripodium 

 and underside it is mouse-coloured. 



The foot is quadrate in shape, and the sole is subdivided longitudinally by two 

 grooves, which divide it into three series of large square corrugations of the epidermis 

 (PL XXXII. fig. 11). 



Text-figure 7. 



Idl. 



Aperture of mantle-cavity in Chronos sublimis. rdl., right dorsal lobe ; Ml., left dorsal lobe ; 

 pn., pneumostome ; ao., anal orifice ; /., foot. 



The sole is surmounted by a broad peripodium, but only one peripodial groove is 

 found. The dorsum of the foot (PL XXXII. fig. 5) is covered with corrugations; those 

 bordering the peripodial groove are square in shape, and are continued on to the 

 median line of the tongue or lappet that covers the caudal mucous pore. The lateral 

 areas of this tongue are separated by grooves from the median portion, and constitute 

 the terminal portion of the peripodium. Right and left dorsal lobes are found, the 

 latter continued practically all round the mantle-edge in an unbroken line (text-fig. 7). 



