RICINULA. 



Plate I. 



Genus Ricindla, Lamarck. 



Testa suboriicitlan- velfmiformi-ovata, sapmime tuberculata 

 aid spinosa, spird nunc Irevlsdmd, depressd, nunc acu- 

 minata; aperturd subangustd, columelld snliexcavafd, 

 inferdmn corngatd aut dentatd, lahro infus dcidato, 

 dentibus nodulosis aut plicaformibus, labri margine 

 intei-dum, autem raro, dlgitato. Operculum conmim, 

 tenue, semilmiare. 

 Shell somewhat orbicularly or fusiformly ovate, most fre- 

 quently tubcrculated or spined, spu'e sometimes very 

 short and depressed, sometimes acuminated ; apertui'e 

 rather naiTOW, columella a little excavated, sometimes 

 wrinlded or toothed, lip toothed within, teeth nodu- 

 lous or plait-like, edge of the lip sometimes, but 

 rarely, digitated. Oporculmii horny, tliin, semilunar. 

 In adopting the genus Riciiiula, I propose to include a 

 much wider range of species than has been hitherto refer- 

 red to it ; namely, that fusiform series distinguished from 

 Buccinum and Purpura by the nodnlous dentition of the 

 inner lip, ai-ranged by M. Kicner as a section of the latter 

 genus, under the significant title of " Les Pourpres semi- 

 ricinules ;" and of which the Purpura fscellum of authors 

 may be regarded as the type. It cannot be disputed that 

 there are species in the genera Bicinula, in its limited 

 acceptation, and Purpura, in which it is difficidt to define 

 any generic difference; as for example, between the P. 

 hjstrix and the R. araclnioides, or between the P. aperta 

 and certain varieties of the R. clathrata ; but the alteration 

 of names in familiar usage should, as far as possible, be 

 avoided. A large proportion of the species I am about to 

 characterize as Riciiiulep, have not been hitherto described, 

 and theii- connection with the Purpuree proper, is one of 

 such very remote athnity, that I prefer elevating the genus 

 under consideration into one of more importance, to the 

 creation of a new genus, or to the fusion of the whole into 

 one, after the manner of the French natm-alists. 



The soft parts of the typical species of Ricinula differ in 

 no respect from those of Purpura, and, in both genera, are 

 furnished with a thin horny opercidimi. 



Species 1. (Mus. Ciuning.) 



Ricinula elegans. Ricin. testa rotuudato-omtd, basi 

 atteuuatd, brevissinid; transversim regulariter spinosa, 

 spinis squamaformibus, prominentibus, marginem versus 

 gradatim lougioribus, uUersiitiis minutissime et pul- 



chfrrime squamatis, columelld labroque intns conspieue 

 dentatis ; alMcante, apo-tnrd eburned, lined vivide ru/d 

 concinne circumdatd. 

 The elegant Ricinula. Shell rotundately ovate, atten- 

 uated at the base, spii'e \ery short; transversely 

 regularly spinous, spines scale-like, prominent, gra- 

 dually longer towards the margin, interstices very 

 minutely and beautifully scaled, lip and columeUa 

 conspicuously toothed within ; whitish, aperture ivory 

 white, very prettily euoircled with a bright red line. 



Brodeeip and Sowekby, Zool. Journ. vol. iv. p. 37G. 

 Beechey's Voyage, MoU. pi. 36. f. 4. 



Hab. Lord Hood's Island (on reefs at low water) ; Cuming. 

 No one can fail to recognize this very rare and delicate 



species by the bright red line which encircles the aperture ; 



iu other respects it mostly resembles the R. arachwides. 



Species 3. (Mus. Cuming.) 



Ricinula digitata. Ricin. testd obovatd, peciiUariter 

 depressd, spird brevissimd ; transversim obtuso-costatd, . 

 vdimtissime crispato-squamatd, costis spiram versus 

 nodosis aut tuberculalis, frondibus depresso-palmatis, 

 superne majoribus, ad marginem desinentibus ; albidd 

 aid lutescente, aperturd vivide luteo-aurantid. 



The fingered Ricinula. Shell obovate, peculiarly de- 

 pressed, spii-e rather short; transversely obtusely 

 ribbed, very minutely crisply scaled, ribs nodose or 

 tubcrculated towards the spu'c, ending on the margin 

 in depressly palmate fronds, the upper of which are 

 the lai-ger; wliitish or yellowish, aperture bright 

 yellowish orange. 



Lamarck, Anim. sans vert. (Deshayes edit.) vol. x. p_. 50^. 

 Ricinula (Purpura) l^a, De Blainville. ')-' ■'■{" " 



Hab. Lord Hood's Island (on the reefs at low water) ; 

 Cuming. 



Variety ^. 



Testa fiisca, aperturd vivide nigricante-eastaned. 

 Shell brown, with the aperture bright dark chesnut. 



Ricinula {Purpura) lobata, D.£&hayes. 

 Hab. Sechelle Islands (on the reefs at low water); Rous- 

 seau. 

 I am sorry to be obliged to differ from two such autho- 

 rities as M. M. De Blainville and Deshayes m regard to 

 the specific rank of the Sechelle Island variety; there 

 cannot be a doubt, in my estimation, of the immediate 



f,' 



August, 1846. 



