GASTEROPODA. 45 



the apex ; interior, above the muscular impression, more or less 

 orange ; below silvery. Height, 1 ; length, 2'2 ; breadth, 1'8. 



Amuri Bluff. Stonyhurst. 



The young shell is more orange, and has the apex sub-anterior. 



NACELLA. 



Ovate, conical, thin ; apex sub-anterior ; mouth simple. 

 Britain. Cape of Good Hope. Cape Horn. 



207. N. radians, Gmelin, p. 3720, No. 144. Oval, narrower in 

 front, depressed, with distant radiating ribs, margin entire but often 

 sub-denticulaied by the sh'glitly projecting ribs. Greenish yellow with 

 black markings, either arranged in a radiating pattern or irregularly ; 

 interior silvery. Height, "25 ; length, 1'2 ; breadth, '9. 



Abundant. Chatham Islands. 



Extremely variable, both in form and colour ; often dark brown or 

 purplish brown. 



208. N. flCXUOSa, sp. iwv. Ovate, depressed, not ribbed, but 

 with fine concentric stria? ; margin entire. Pale yellowish with deeply 

 waved concentric brown lines ; interior silvery. Height, '6 ; length, 

 1-7 ; breadth, T4. 



Stony hurst. 



209. N. earli, Reeve. Oval, narrower in front, depressed, with 

 fine, rather high, radiating striae, margin crenated. Brownish oliva- 

 ceous, interior shining silvery. Height, '3 ; length, '95 ; breadth, '8. 



Bluff Harbour ; Wellington Harbour. 



210. N. stelllllaria, Quoy, I.e., iii., p. 347. Oval, depressed, 

 with small granular ribs. Reddish, with white rays at the apex, or 

 two white lines at the posterior end ; interior white. Height, '3 ; 

 length, 1'4 ; breadth, I'l. 



211. N. argentea, Quoy, I.e., iii., p. 345 ; P. decora, Reeve. 

 Ovate, convex, thin, radiately ribbed; ribs numerous, small, smooth, 

 slightly undulated, obsoletely decussated with concentric striae ; 

 greenish olive or yellow, with distant radiating black or red bands ; 

 interior silvery. Height, '35 ; length, '95 ; breadth, '75. 



Variable in colour and in height, sometimes depressed, sometimes 

 semi-globose. 



* 212. N. flOCCata, Reeve. Shell ovate, convexly depressed, 

 apex inclined anteriorly ; flattened, radiately finely ridged ; ridges 

 thread-like, slightly waved, delicately crenulated with concentric striae. 

 Olive green, profusely sprinkled with white flakes ; interior vivid blue 

 green. {Reeve.) 



This appears to me to be a variety of N. argentea. 



* 213. N. affinis, Reeve. Shell oblong ovate, depressed, apex 

 very anterior, small, rather sharp ; radiately ridged and striated, ridges 

 and striae numerous, obtuse, slightly waved. Dark olive, ornamented 

 with obliquely blood-blotched broad rays ; interior sub-transparent, 

 iridescent. 



