PURPURA, 



Plate III. 



Species 11. (Mus. Cuming.) 



Purpura Asceksionis. Purp. testa globosd, cru^sa, per- 

 solidd, spird plano-depremd ; lavigatd aiit suUiUter 

 striata; columeUd latisshud, plano-concavd, labro mi- 

 nute denticulato, superne canaliculato ; extus transver- 

 sini subtilissime castaiieo-striatd, iiitus eburned, colu- 

 mella ebumed, maculis atris tribus aut pluribus aut 

 minoribus conspicue notatd. 



The Ascension Purpura. Shell globose, thick, very 

 solid, spire flatly depressed ; smooth or finely striated ; 

 colimieUa veiy broad, flatly concave, lip minutely 

 denticulated, channelled at the upper part ; exterior 

 transversely very finely striated with chesnut brown, 

 interior ivory white, columella ivory white, conspi- 

 cuously with three, more or less, jet black spots. 



QuoY and Gaimard, Voy. de I'Astrolabe, Zool. vol. ii. 

 p. 559. pi. 37. f. 20 to 23. 

 Miirex Mcega (pars). Martini. 



Hab. Island of Ascension, Atlantic (on rocks at low 

 water). 



I am not surprised that Martini should have represented 

 this, and the following species, under one name ; it may be 

 more convenient to preserve the distinction assigned to 

 them by M. (iuoy, but, that they are e.xtreme modifica- 

 tions of the same thing I have no doubt ; I attach greater 

 importance to the brown hair-like lines which characterize 

 these species, than to the presence or absence of tubercles. 



Species 12. (Mus. Cuming.) 



Purpura Neritoidea. Purp. testd, suborbiculari, ven- 

 tricosd, crassiusciild, spird brevissimd, depresnd ; trans- 

 versim striatd, tubercuUs soUdis promhieutlhus seriatim 

 cinctd ; colamelld lata, concavo-planatd ; albidd, lineis 

 subtilibus castaneis plus minusve pictd, aperturre fauce 

 eburned, maculis atris tribus aut pluribus aid minoribus 

 notatd. 



The Nerite-like Purpura. Shell nearly orbicular, 

 ventricosc, rather thick, spu'e very short, depressed ; 

 transversely striated, encircled with rows of promi- 

 nent solid tubercles ; columella broad, concavely 

 flattened ; white, more or less painted with fine 

 chesnut lines, interior of the apertm'c ivory white, 

 columella ivory white, marked with tlu'ee, more or 

 less, jet black spots. 



Deshayes, Anim. sans vert. v. x, p. 70. note 

 Purpura Neritoidcs, Lamarck. 



Murex Neritoideus, Linnaeus (12th. ed. Syst. Nat.). 

 Nerita nodosa, Linnseus (10th. edit. Syst. Nat.). 

 Murex Moega, (pars altera), Martini. 

 Murex fucus, Gmelin. 

 Purpura fuciis, Sowerby, De Blainville. 

 Hab. Island of St. Vincent, Cape de Verds. 



The confusion indicated by the above synonymes arises 

 mainly from the circumstance of Linnaeus having referred, 

 for the illustration of his Murex Neritoideus, to figm'cs of the 

 Ricinida horrida, as well as of the shell under considera- 

 tion ; M. Deshayes clearly shows, however, that Gmelin 

 and his followers are in error, the character "cotemeWa 

 planiuscidd " used by Liimajus, being quite inapplicable to 

 that species. 



Species. 13. (Mus. Cuming.) 



Purpura hystrix. Purp. testd ovato-globosd, snbventri- 

 cosd, umbilicatd, spird breviusculd, acuminatd ; squa- 

 mis grandibus spiniformibus forwicatis seriatim ornatd ; 

 subtiliter liratd, liris minutissime squamafis, columeUd 

 convexd, basi exiliter rugatd, labro intus denticulato ; 

 lutescenie, columeUd et apertura fauce roseis. 



The porcupine Purpura. Shell ovately globose, slightly 

 ventrieose, umbilicated, spire short, acuminated ; 

 ornamented with rows of large prominent spiniform 

 vaulted scales, transversely finely ridged, ridges very 

 minutely scaled; columella convex, faintly wrinkled 

 at the base, lip toothed within ; yellowish, columella 

 and interior of the aperture rich pink. 



Lamarck, Anim. sans vert. (Deshayes' edit.) v. x. p. 85. 

 Murex hystrix, Linnanis. 

 Eadem Purpura spathulifera, De Blainville (according 



to M. Kiener). 



Hab. Island of Annaa, south Pacific Ocean (on the coral 

 reefs at low water) ; Cuming. 



This species is one of those intermediate states between 

 Purpura and Ricinnla, which have induced some of the 

 continental naturalists to combine the two genera in one. 

 Although it may be referred with equal propriety to either, 

 I think it convenient to perpetuate the generic appellations 

 of Lamarck ; all limitations of genera become less defined, 

 as the links which are wanting in the chain of affinity 

 become revealed to observation ; if this system of fusion 

 were followed out, the nomenclature would be completely 

 overthrown. 



Julv, 1846. 



