BY H. LEIGHTON KESTEVEN. 535 



and larger than in the type, due to the absence of a porcellanous 

 thickening on the interior of the outer lip. The revolving lirae 

 in the aperture are finer, more numerous, and stained dark brown. 

 Proportions as in the type. 

 • Hah. — New South Wales and Lord Howe Island. 



Type to be presented to the Australian Museum. 



The purpuroid characters of the adult shell are in the aperture. 

 The columellar area is broad and flattened, and the thickened and 

 Urate outer lip is decidedly characteristic of the genus Purpura. 

 The sculpture of var. smithi is not unlike (in miniature) that 

 of P. succincta, Martyn. 



Several apices of the same type as that of P. tritonifo7'inis 

 have been treated as adult mollusca, and as their history bears 

 directly on the conclusions I have arrived at, I give the following 

 resume of it. 



The first of these was described by Gray* as Struthiolaria 

 microscopica. The second is that described by D'Orbignj^f as 

 Sinusigera cancellata. The third is Cheletrojns huxleyi of Forbes. % 

 Others were meagrely described by A. Adams in various papers 

 in the Annals and Magazine of Natural History, and others again 

 by Craven§ in his Monograph of the genus Sinusigera. The 

 principal conchological feature of the three mentioned was the 

 possession of claw-like lobes on the outer lip, such as are so plainly 

 shown by my fig. 4. 



Dr. J. D. Macdonald|| pointed out the anatomical similarity of 

 Sinusigera (Cheletropis) huxleyi to Macgillivrayia j^elagica, Forbes 

 {loc. cit. p. 383), another pelagic gasteropod embryo; and, being 

 under the impression that they were adult molluscs, suggested 

 that they should be placed in an order by themselves. A. AdamslI 

 wrote that the genus Sinusigera belonged to the Macgillivrayidce, 



* Zool. Voy. Blossom, 1839, p. 108. 



+ Hist. Pol. y Nat. de Cuba, 1846, Moll. Vol. v., p. 241. 



J Voy. Kattlesnake, 1852, Vol. ii. Append. 385, pi. iii., figs. 9 a and h. 



§ Ann. Soc. Mai. Belgique, 1877, Vol. xii. 



II Phil. Trans. 1854, Vol. 145, pp. 289-297. 



H Ann. Mag. Nat. Hist., June, 1857, p. 461. 



