ODOSTOMIA. 275 



grow to a quarter of an inch long, in which case the spire 

 is generally more produced than ordinary. Another variety, 

 in which the spire is shorter than the mouth, has the 

 whorls so shouldered, as actually to be scalariform. The 

 single si^ecimen from which the 0. noiata was constituted, 

 appears to us to be a broken-mouthed solid variety of this 

 species, in which the whorls are rounder than usual, and 

 the spiral striulee a little more manifest. 



" The mantle of the animal is plain. The head is a 

 short muzzle, marked on each side with a pale yellow longi- 

 tudinal line, mouth vertical ; the head issues between the 

 foot and tentacular veil ; the tentacula coalesce at the base 

 and are short, subtriangular, bevelled like the awl, not 

 pointed, setaceous, flattened, and in some animals the 

 yellow white ground colour is sufl\ised with sulphur yel- 

 low, each has also a longitudinal intenser line running 

 between the bevels, the eyes are at their internal angles, 

 planted in the skin. The general colour of the animal is 

 pale yellowish white. The foot is short, truncate in front, 

 auricled, but not emarginate in the centre, nor hollowed 

 out as in 0. acuta ; it is rounded posteriorly and terminates 

 suddenly in a short blunt point, it is powdered on its 

 upi)er surface, with pale gold-colour minute dots, and in 

 some specimens with sulphur yellow points ; beneath the 

 same colours prevail, though less intensely ; a simple upper 

 lobe carries a light corneous suboval striated operculum. 

 This species is far more variously coloured than any of its 

 congeners I have seen. The minute branchial plume, the 

 only one I have observed, was found under the mantle 

 at the usual place. The anal pellets were seen discharged 

 from the right side. The reproductive and lingual organs are 

 unknown. 'I'his species differs nothing in essentials from 

 0. acuta ; the only variations are of colour, and in the an- 



