34 GASTEROPODA. 



reddish brown and white; interior white, iridescent. Length, '85 ; 

 breadth, 1 ; angle of spire, 75. 



Common. Chatham Islands. 



Not so much depressed as the last, and the granulations smaller. 



* 142. T. undulatUS, Reeve. Shell orbicular, broadly and 

 deeply umbilicated ; whorls sometimes grooved, sometimes smooth. 

 Bluish green, longitudinally marked with white zig-zag streaks. 

 {Reeve}. 



IMPERATOR. 



Trochiforni, thick, with a flat or concave base ; whorls keeled, or 

 stellated ; aperture angled outside ; operculum shelly, concave outside 

 with a spiral rib. 



West Indies. South Africa. India. Australia. 



143. I. (Cookia) COOkil, Lamark, I.e., ix., p. 131. Conical, 

 body whorl rather ventricose ; whorls rounded, obliquely plaited and 

 crossed by oblique rough imbricating lamiuse sloping the opposite way 

 to the plaits ; central part of base smooth, hollowed in the middle. 

 Pinkish brown ; pearly inside. Length, 2'25 ; breadth, 3'5 ; angle of 

 spire, 86 to 92. 



Common. Chatham Islands. 



144. I. (Cookia) davisii, Stowe, Trans. N.Z. Inst., iv., p. 

 218. Conical ; body whorl sharply angled and keeled ; whorls slightly 

 rounded, obliquely plaited and crossed by oblique rough imbricating 

 laminae sloping the opposite way to the plaits ; central part of the base 

 smooth, scarcely hollowed in the middle. Pinkish brown ; pearly 

 inside. Length, 3'65 ; breadth, 3'3 ; angle of spire, 57 to 60. 



Cook Strait and Blind Bay. 



The spire is much more acute than the last, but perhaps it is only 

 a variety. 



145. I. (Astralium) imperialis, Lamark, i.e., ix., p. 122. 



Conic, obtuse, whorls convex, with spiral scaly ribs, and a spinose 

 radiate margin ; spines curved to the left and backwards ; perforation 

 funnel-shaped, extending to the apex. Above purplish or reddish 

 purple ; base nearly white ; interior iridescent. Length, 1'S ; breadth, 

 35 ; angle of spire, 110. 



From Hauraki Gulf to Stewart's Island. Chatham Islands. 



In the young shell the marginal spines are fewer and longer than 

 in older ones. As the animal gets older the upper spines break off to 

 the base, and get so covered with coralline growth that they are diffi- 

 cult to distinguish. 



Allied to 1. longispina from the "West Indies. 



LIOTIA. 



Turbiuated, globular, or discoidal, perforated ; spire depressed ; 

 aperture rounded, pearly ; peristome thick. 



South Africa. India. Philippines. Australia. 



