16 GASTEROPODA. 



FAMILY 



Shell various, aperture large ; animal with a small head and foot ; 

 operculum oval-oblong, nucleus lateral. 



PURPUPvA. 



Shell ovate ; spire short ; aperture slightly notched in front ; col- 

 umella flattened or concave. 

 Warm and temperate seas. 



48. P. haUStriim, Marti/n ; Quoy, I.e., ii., p. 554. Ovato- 

 ohlong. ventricose, spire depressed, rugose, spirally striated ; outer lip 

 thin, wrinkled ; columella hollowed, canal large. Brown ; interior 

 greyish white, with a broad band of brownish purple on the right lip, 

 and generally a spot of the same at the posterior end of the columella. 

 Length, 3 ; breadth, 2 ; angle of spire, 90. 



Chatham Islands. 



49. P. (Polytropa) textiiiOSa, LamarJc, I.e., x., p. 77. Shell 

 ventricose, broadly spirally grooved, each groove with from one to four 

 smaller raised ridges, the main ridges also with one or t\vo small 

 grooves ; finely transversely striated ; outer lip creuulated and grooved 

 internally, margin thin. Yellowish white ; columella white ; inside 

 yellow, with a white baud round the margin of the outer lip. Length, 

 29 ; breadth, 18 ; angle of spire, 73 to 05. 



50. P. (Polytropa) SUCCincta, Lamarlc ; Buccinum lacuno- 

 sum, Brug. ; P. rugose/-, Lamark (young); nee. Qifoy ; P. emarginata, 

 Deshayes. Shell veutricose, deeply and broadly spirally grooved, the 

 grooves crossed by thin, rather distant, transverse lamella?, which do 

 not reach as .high as the tops of the ridges ; ridges smooth ; outer lip 

 crenulated and grooved, margin rather thick. White or yellowish 

 white; inside white, nacrous. Length, 2'3 ; breadth, i'5 ; angle of 

 spire, GS. 



Chatham Islands. 



51. P. mgOSa, Q lf oy, l-c., ii., p. 569; nee. LamarJc. Ovato-acute, 

 spire pi'oduced ; whorls narrowly, rather distantly, spirally grooved, 

 rough with numerous thin imbricating transverse foliations ; outer lip 

 crenulated and grooved ; columella with one fold. Brownish white ; 

 interior purple, columella and a band round the mouth white or 

 yellowish. Length, - 75 ; breadth, '45 ; angle of spire, 54. 



52. P. (Polytropa) SCQbina, Quoy, I.e., ii., p. 567 ; P. albo- 

 marginata, Deshayes. Ovate or oblong, spirally ribbed, rough with ir- 

 regular undulated transverse lamella? ; spire produced ; spire whorls 

 cariuated, nodulose ; outer lip crenulated and grooved ; columella one 

 plaited ; canal large. Brown ; interior brownish purple. Length, 1 ; 

 breadth, '6 ; angle of spire, 60. 



Common. 



This shell is easily distinguished from P. ruyosa by the transverse 

 lamella? being more irregular and lying flatter. It is generally much 

 worn and often covered with barnacles. 



