GASTEROPODA. 57 



suture linear ; whorls nine, flat, the last forming about two-thirds of 

 the total length, rather swollen above, somewhat lessened towards the 

 base, with a swollen tubercle ; aperture perpendicular, narrowly semi- 

 ovate, rounded in front ; one middle-sized, rather transverse plait on 

 the last whorl ; colurnella plait obliquely produced to the margin ; 

 peristome acute, bordered with brown ; right margin furnished with a 

 white callus, which sends off eight or nine short ridges ; colurnella 

 margin slightly thickened. Length, '35 ; breadth, - 2. (Pfeiffer^) 



267. M. COStellariS, Adams, I.e., p. 12 ; Pfeifer, I.e., p. 39. 

 Auricula zealandice, Hector, Cat. Col. Mils., 1870, p. 98 (name only'). 

 Shell rhnate, ovato-conic, solid, ribbed longitudinally, brown, with 

 irregular pale streaks ; spire conic, blunt ; suture irregularly impressed ; 

 whorls five or six, the upper ones flat or rather excavated, the last 

 forming about four-sevenths of the total length, very obsoletely angled, 

 and girdled with a pale line at its upper circumference, somewhat 

 tuberculate at the base ; aperture nearly perpendicular, sinuately 

 ovate ; parietal plait one, strong, deep, rather transverse ; columella 

 plait a little smaller, produced externally ; peristome blunt ; right 

 margin sinuated above, then thickened by an internal deposit ; colu- 

 mella margin dilated, rather aduate. Length, '47 ; breadth, '26. 

 (Pfeiffer.) 



* 268. M. SUlcatUS, Adams, I.e., p. 34. Shell sub-rimate, ovate, 

 solid, sculptured above with crowded granular ridges, brown, with 

 three pale bands ; spire conic, obtuse ; suture linear, slightly canal- 

 iculate ; whorls five, flat, the last forming two-thirds of the total 

 length, slightly angulated above, then more distinctly grooved spirally, 

 furnished at the base with a very slight keel surrounding the um- 

 bilical region ; aperture scarcely oblique, semi-ovate, showing the same 

 colour and bands within ; parietal plait one, compressed, transverse ; 

 columella plait scarcely smaller, rather oblique; peristome straight, 

 sharp ; columella margin somewhat spreading in adult specimens. 

 Length, '5 ; breadth, '25. (Pfeiffer.} 



CASSIDULA. 



Shell rimate, cassidiform, solid ; spire short, conoidal ; last whorl 

 large, attenuated at the base, provided usually with a keel surrounding 

 the umbilical region ; aperture narrow, sinuate ; body of the last 

 whorl bearing various teeth ; columella plait strong ; right margin of 

 the peristome thickened with a longitudinal internal callus, which is 

 sinuated above. 



Australia. Indian Archipelago. Philippines. Otaheite. Mauri- 

 tius. South Africa. 



269. C. HlUStelina, Deshayes ; Pfeiffer, I.e., p. 89. Shell sub- 

 rimate, ovate, conoidal, slightly spirally striated, dark brown, marked 

 usually with four unequal white or bluish bands ; spire short, conoidal, 

 rather pointed ; suture linear ; whorls seven, the upper ones almost 

 flat, the last forming about four-fifths of the total length, ventricose, 

 furnished at the base with a white arched keel, and with a second near 

 the umbilical groove ; aperture nearly perpendicular, elongate, rounded 

 8 



