280 Mr. Swainson's Monograph 



Inhabits the Indiaa ocean. It is an uncommon shell, and is here 

 described from a beautiful specimen in Mr. Broderip's cabinet. 



This, I have no doubt, is the true ventricosa of Lamarck : for, as 

 far as his description goes, it is very correct. With regard to 

 the figures which he has cited, it is clear that no reliance can be 

 placed on that of Martini, 2 tab. 65, f. 731 ; for Lamarck has 

 quoted this same figure twice, for two different shells. Lister's 

 (tab. 746) is as badly defined, and both are among those, which 

 no accurate writer should venture to cite, as an authority for any 

 particular species. The best, and indeed the only tolerable repre- 

 sentation of this shell that I have met with, is to be found in this 

 Journal, vol. xvi, plate 5, f. 206 *, and does great credit to the 

 talents of the lady who designed it : the crenated lip will only be 

 observed in very perfect and adult specimens. 

 ** Spire pi-oduced. 



The few species included in this group, form a natural and 

 beautiful passage, by which the imperforate and perforate sections 

 are united. The spire here occupies one-half of the total length of 

 the shell ; or, in other words, is as long as the aperture. In all the 

 species, there is a thickened belt of enamel, which margins the 

 suture of the body whorl, and in the recent species, there is a 

 third belt at the base, which is very narrow, and composed of two 

 indented parallel lines, terminating in obtuse teeth on the margin 

 of the lip ; this character likewise belongs to the perforate species. 



8. Ancillaria marginafa. Lam. 



A. testd ovatd, veiUricosS, albente, sutura carinatS,fusco-maculatd ; aper- 

 turee spineqiie longitudine cequali. 



Shell ovate, ventricose, whitish, suture spotted with brown, and cari- 

 nated ; aperture and spire of equal length. 



A. Marginata. A. ovata, ventricosa, alhida ; spird acufd, carinulatd, 

 inleiTupte fasciatd; labro basi unidenlato. Lamarck, Ann. du Mus. 

 xvi, p. 30 1. 



A. Marginata. A. testd ovatd, venlricosd, albidd ; spird exserto-acutO , 

 carinvlatd ; anfractibus siiperne maculis rtifis seriatitii marginatis ; 

 aperturd basi emarginatd ; callo columellari angusto, striaio. La- 

 marck, Hist. Anim. sans Vert. 7, 413, No. 3. Ency. Melh. pi. 393, fig. 

 2. a. b. 



* It is there called, by mistake, A. cinnamomea. 



