Kglisii, Callostracnm, iSIe-iali}-, i(c. .^07 



in tlic aperture and tlio operculum, wliicli is pauci.spiral, like 

 Littorina, and not multi.spiial, as in Turriulli. 



The fi;rurcs in Adams ((Jenera Recent Moll. vol. iii. 

 pi. xxxviii. fig3. 4a, 4ih) icpresent tlie operculum of the 

 genus Turritella, and not that of Me.salia. 



Tliis inistako led Dall * into the error of statin;? that the 

 opercula of Meaalia and Tar/ii/rhj/nchua {Menalia reticulata) 

 jueaentel no difference. The liict is, that of the former con- 

 sists of four or five rapidly enlar^'^ing whorls with a somewhat 

 excentric nucleus, whereas that iu tiie latter genus is inulti- 

 Hj)iral, with central nucU-us. 



The opercula of typical examples of }f. brevidlis, from 

 Goree, in the British Museuu), are almost black, rather con- 

 cave externally in the dried state, aud consist of four or five 



rapidly increasing volutions, somewhat carinate at the suture 

 towards the det p nucleus, and with a raised spiral thread 

 upon them wliicli dues not extend to the last two large whorls. 



MfsaHa hrcv'uihs (Lama:ck). 



l"o7. Cerithiitm mesal, Adanson, Hist. Xat. Senegal, p. xcv, Le Mesa], 



p. lo9. pi. X. 

 1822. Turritella breciaUs, I>aniftrck, Anim. sans vert. vol. vii. p. o8. 

 164"}. Tiarittlla brevialis: Kieiier, Coq. Viv. p. 40, pi. xii. tigs. 1, 1 a. 

 1843. Turritella viesal, Desbayes, Auiui. sans vert. ed. 2, vol. ix. 



p. 2G1. 

 1847. Mesalia meml : Gray, Proc. Zool. Soc. 1847, p. 155. 

 1849. Mfsalia brerittlvi: Keeve, Conch. Icon, vol. v. pi. v. fig. 10 o 



{Turntelia), fig. 2 A {Meitalia). 

 1852. Mesalia brevialU : Sowerby, Conch. Man. ed. 4, p. 201, pi. ixviii. 



ti^'. 691. 

 1854. Mesalia brevialia : II. & A. Adams, Gen. Rec. Moll. vol. i. p. 354, 



pi. xxxviii, fig, 4, shell (4 a, 4 6, represent the operculum of 



Turritella). 

 1857. Mesalia brerialis: Gray, Guide Moll. Brit. Mus. p. Ill, 

 1859. Mesalia brevialia : Chenu, Man. Concb. vol, i. p. 317, figs. 2284, 



2285. 



* Amcr. Journ. Conch, vol. vii. p. 1U<. 



