42 



on the back from pinkish white, mottled with brown, to 

 greyish white, mottled with black. India. Ceylon. 



3. Pt. Aurantia. (pi. xi. f. II.) Lam. Anim. sans Vert, 

 vii. p. 198. 



T. sub-quadrata, spiraliter striata, seriebus tribus 

 tuberculorum cincta, alba, rufo-maculata ; apertura elongata, 

 aurantiaca, lsevi, canalibus duobus et digitis quinque tenuis, 

 arcuatis, elongatis ; labio interno angusto, antice gibboso. 



The digitations of this smooth orange-mouthed species are 

 elongated, slender, and curved upwards. East Indies. 



4. Pt. Chiragra. (pi. xi. f. 12.) Lin. Syst. Nat. p. 1207. 

 T. ponderosa, magna, spiraliter costata, ad angulum 



tuberculata, rufa, pallide fulva, fusco-maculata ; apertura 

 excavata, interne plicata, rosea, nigrostriata ; canalibus 

 terminalibus (postico preecipue) recurvis, digitis marginalibus 

 quatuor arcuatis, una inter canalem et sinum ; labio interno 

 gibboso, nigrescente, interne striate 



In this well known species the posterior canal is strongly 

 recurved and bent downwards over the spire as far as the 

 angle. The digitations are large and strongly curved ; one of 

 them being placed on the lobe between the sinus and the 

 canal ; the aperture is deep. East Indies. 



5. Pt. rugosum. (pi. xi. f. 9. 10.) nobis. 



T. crassa, sub-ovali, spiraliter striata, ctistis quatuor 

 nodulosis cincta, digitis crassis, arcuatis, terminalibus, 

 recurvis, una inter sinum anticum et canalem; apertura; lata, 

 valide excavata, intus uniplieata, sulcis nigris striata; labio 

 interno sulcis nigris striate 



After careful examination, we have arrived at the conclusion 

 that this shell, although generally regarded as a mere variety 

 of Pt. Chiragra, is perfectly distinct. The principal difference 

 consists in the comparative smoothness and hatness of the 

 inner lip and the strong downward curve of the posterior canal, 

 which reaches the angle of the body whorl in Pt. Chiragra. Pt. 

 rugosum is thick, sub-oval, spirally striated, with four tubercu- 

 lated ribs on the body whorl, below the angle. The digitations 

 are thick and curved, the posterior terminal one, although 

 somewhat recurved is not bent downwards over the spire, as 

 in Pt. Chiragra. The aperture is wide, and very deep, with 

 the interior strongly plicated, and transversely sulcated with 

 black interstices ; the inner lip is sulcated in the same manner. 

 The general colour of the shell is light brown mottled with 

 darker touches and blackish stripes on the terminations of the 

 digitations. The aperture is more or less strongly tinctured 

 with rose colour ; the black striped grooves covering a larger 



