M I T R A. 



Plate I. 



Genus Mitba, Lamarck. 

 Testa vel oblongo-ovata, vel fusiformi-elongata, spird 

 acuminatd, apice sapissimc acuta ; anfractibus nunc 

 Icevibus, nunc casta! is ; columella basim versus plus 

 minusve recurvd, plicatd, plicis infimis minimis; 

 aperturd angustd, testis longitudinem interdum fere 

 aquante ; labro subincrassato, plerumque denticulate, 

 .Shell oblong-ovate or fusiformly elongated, spire acu- 

 minated, apex most frequently sharp ; whorls some- 

 times smooth, sometimes ribbed ; columella more or 

 less recurved towards the base, plaited, lowest 

 plaits the smallest ; aperture narrow, sometimes 

 nearly equalling the length of the shell ; lip some- 

 what thickened, generally denticulated. 

 The genus Mitra, instituted by Lamarck, is the most 

 numerous division of that rich and rare family of pectini- 

 branchiate gastropods, the Colume/lata, and the species 

 have been much admired for their symmetry and variety 

 of colour. Although the shells of this genus were called 

 *' Mitres" soon after the revival of letters, Linnaeus still 

 arranged them with the Volutes ; they were, however, 

 separated by Lamarck on account of their narrow turri- 

 culated growth and other differences, not the least im- 

 portant of which are, that the apex is never papillary, 

 and the plaits, instead of increasing, diminish in size to- 

 wards the base. Some species of Mitra approximate 

 very closely to the Columbelke, but may be easily distin- 

 guished by remarking the strong generic difference that 

 exists between the columellar plaits of the Mitres, which 

 entwine the pillar of the shell throughout its entire 

 growth, and the plait-like denticulations of the Colum- 

 bella, which are not developed until the shell arrives at 

 maturity. 



Lamarck described about eighty species of Mitra, all 

 of which, with the exception of one or two, I have iden- 

 tified in the collections of Mr. Cuming and Mr. Norris ; 

 several of these were previously described as Volutes ; 

 some by Linna?us, and some by Dr. Solander under other 

 specific names in his catalogue of the Duchess of Port- 

 land's collection, which, as they exist only in manuscript, 

 cannot in justice to foreign authors be quoted or consi- 

 dered of any authority. To Lamarck's species were 

 added about fifty, described by Swainson in the ' Exotic 

 Conchology,' 'Zoological Illustrations,' and 'Proceedings 

 of the Zoological Society' (through Mr. Broderip) for 

 1835 ; and I have now as many new species as will 

 increase the number to considerably above two hundred. 

 [Mr. Swainson contributed greatly to the interest of 



the genus Mitra by the zeal and enthusiasm with which 

 he both described and illustrated the species just re- 

 corded ; that eminent zoologist, however, towards the 

 latter part of his career in this country, became infatu- 

 ated by certain hypothetical notions of systematic ar- 

 rangement in which he entirely lost himself. He con- 

 ceived that every character, however unimportant, is re- 

 presented by the most perfect analogy throughout the 

 different classes of animals, within very prescribed 

 limits ; that the Volutes and Mitres for example " repre- 

 sent the Rasorial type among Birds, the Ungulata among 

 Quadrupeds, and the Thysanura among Insects." These 

 flights of analogy he proposed to exhibit in circles ; and 

 they revolved in his imagination in such mystical order 

 as to reveal the most incomprehensible affinities.] 



Species 1. (Mus. Cuming.) 

 Mitra lens. Mitr. testa subobeso-fusiformi, turritd ; 

 anfractibus longitudinaliter plicato-costatis, costis 

 latis, rudibus, plano-obtusis, transversim impresso- 

 striatis, striis subdistantibus, duabus medianis inter 

 costas peculiariter foraminatis ; einereo-violaced, epi- 

 dermide corned nigricante-olivaceo indutd ,■ columelld 

 quadrip/icatd, plicis grandibus ; apertura fauce pur- 

 purascente-cinered. 

 The lentil Mitre. Shell rather stoutly fusiform, 

 turreted ; whorls longitudinally plicately ribbed, 

 ribs broad, rude, flatly obtuse, transversely im- 

 pressly striated, striae rather distant, the two middle 

 stria; peculiarly holed between the ribs ; ashy violet, 

 covered with a horny blackish olive epidermis ; co- 

 lumella four-plaited, plaits large ; interior of the 

 aperture tinged with purple ash-colour. 

 Voluta lens, Wood, Ind. Test Supp., pi. 3. f. 28. 

 Tiara foraminata, Swainson. 

 Mitra Dupontia, Kiener. 

 Hab. Panama, St. Elena and isle of Plata (dredged from 

 sandy mud and gravel at a depth ranging from six 

 to fourteen fathoms) ; Cuming. 

 This species being so imperfectly figured in Wood's 

 Index Supp., may account for its having been described 

 under different names at three somewhat distant periods. 

 The double row of holes with which each whorl is per- 

 forated round the middle forms nevertheless a very 

 characteristic feature. 



