PURPURA. 



Plate I. 



Genus Purpura, Lamarck. 



Testa ocata vel ohlongo-ovnta, plerumque nodidosa vel tuber- 

 cttlafa, spirdbrevi, anfractu ultimo tmnido, plus mimmve 

 inflatd, aperturd dilatatd, fauce stspissime sulcatd; basi 

 emart/inatd; coltmelld plus minusve depresso-pland ; 

 lahro plerumque dentlculato. 



Shell ovate, or oblong-ovate, generaUy nodulous or tuber- 

 eulated, spire short, last whorl swollen, more or less 

 inflated, aperture dilated, interior most frequently 

 grooved ; base emarginated ; columella more or less 

 depressly flattened ; lip generaUy denticulated. 



The terms Kiypul, Murex, and nop(pvpa. Purpura, were 

 used indiscriminately by ancient Greek writers in reference 

 to all moUusks yielding a pui'ple juice, and they became 

 objects of especial interest in that remote age, on account 

 of the Umited som-ces then known of obtaining colom-. 

 Who has not heard of the purple dye produced by the 

 ' Tyrius murex' of Ovid, {Murex truncidus Linn.)? which 

 no doubt abounded on the shores of the ancient Phsenician 

 city of Tyros. 



The purple juice of the moUusk affords, however, no 

 assistance to the systematist ; it abounds alike in animals 

 of very dissimilar character ; in Scalaria and lanthiiia, as 

 well as in Murex and Purpura ; hence the term Purpura 

 was adopted by Lamai'ck to distinguish the genus \mder 

 consideration, regardless of any property with which the 

 animal might be endowed of secreting a purple juice. The 

 most striking feature in the soft parts of Purpura is that 

 of the head being a little flattened, and prolonged at each 

 extremity into the tentacles, without any prominence in 

 the centre ; approximating in this respect to Buccinum. 

 The tentacles ai'e peduncidated to generally two thu-ds of 

 their extent, and at the summit of the pedunculated portion 

 are the eyes. The operculum which the animal carries on 

 the hind extremity of its disk, is invariably horny, and fits 

 closely to the aperture of the shell. 



The shell of Purpura is mainly distinguished by an 

 ovate dilated growth, emarginated at the base, with a more 

 or less flattened columella, the spire being sometimes ex- 

 tremely short, sometimes a little acuminated. There are 

 three closely aUied genera, Concholepas, Monoceros, and 

 Rkhmla, which the French authors propose to fuse into 

 the present ; I have not considered it prudent, however, 

 to foUow this course, as they afford good typical dis- 

 tinctions, whilst their amalgamation xuider the head of 



Purpura would only tend to confusion by involving a 

 change of names. 



The PurpurcB vary exceedingly in their detaU of sculp- 

 ture, but are somewhat constant in colom- ; the well-known 

 P. lapillus of Europe varies, however, in both respects to 

 an abnost inconceivable degree ; indeed, no one who has 

 not thoroughly examined a numerous series of specimens 

 can form an adequate idea of its Protean character. 



Species 1. (Mus. Cuming.) 



Purpura echinulata. Pmp. testa ovatd, subventricosd, 

 spird brem, tranmersim temdsshne striatd el fiqnamoso- 

 tuberculatd, tubercuUs subechimdatis ; eolumelld latius- 

 culd, concavd ; aperiurd ampld, dUatatd, superne 

 canaliculatd, fauce lirafd, liris distantibus ; luteo-albi- 

 cante, eolumelld et aperturie fauce aurantlo-hdescenti- 

 bus, liris albidis. 



The prickly Purpura. Shell ovate, rather ventricose, 

 spii'e short, transversely very finely striated and squa- 

 mosely tuberculated, tubercles somewhat prickly ; 

 coliuneUa rather broad, concave ; aperture large, 

 dilated, canaliculated at the upper part, ulterior 

 ridged, ridges distant ; yellowish white, columella 

 and interior of the apertiue orange yellow, ridges 

 whitish. 



Lamarck, Anim. sans vert. (Deshayes' edit.) vol. x. p. 84. 

 Eadem, (fide Deshayes), Purpmra mancinelloides De 

 Blainvdlle. 



Hab. PhiU])pine Islands, Cuming. 



The aperture of this species is larger and more dilated 

 than tliat of the P. maucinella. 



Species 2. (Mus. Cuming.) 



Purpura mancinella. Purp. testd ovatd, erassiusculd, 

 spird brevi, transversim feriuissime striatd et costatd, 

 costis distantibus, angtistis, compresso-nodosis ; aperturd 

 superne canaliculaM, fauce lineatd, lineis elevatis, con- 

 fertis ; luteo-albicante, nodis inferdum rufo-fuscis, eolu- 

 melld lutescente, aperlura fauce rufo-aurardid, lineis 

 saturatioribus. 



The pimpled Purpura. ShcU ovate, rather thick, spire 

 short, transversely very finely striated and ribbed, ribs 

 distant, narrow, compressly nodided ; aperture cana- 

 liculated at the upper part, interior lineated, lines 

 elevated and close-set ; yellowish white, nodules 



October, 1846. 



