R A N E L L A. 



Genus Ranella, Lamarck. 



Testdovatd vel oblongu-ovatd , spini plus minusee acumina- 

 ta ,- varicibus stepissime obliquis, ml partem anfractHs 

 dimidiam depositis, seriem longitudinalem utroque la- 

 tere efformantibus ; canali nunc brevissimo, nunc lou- 

 giusculo ; aperturd ovatd, plerumque utrinque canali- 

 cii/atii. 



Shell ovate or oblong-ovate, spire more or less acumi- 

 nated ; varices most frequently oblique, deposited 

 at every half-whorl, forming a longitudinal row on 

 each side ; canal sometimes very short, sometimes 

 rather long; aperture ovate, generally canaliculated 

 at both ends. 



The genus Ranella was established by Lamarck for 

 the reception of that portion of the varicose Canali fcra 

 which construct a varix upon every half- volution. By 

 this lateral deposit of the varices the shell acquires a 

 more or less depressed two-edged structure, and this 

 joint peculiarity of growth is all that has been thought 

 necessary to determine the character of the genus. 

 Various imperfect notions have been entertained by 

 naturalists as to the purpose and influence of varices in 

 the structure of canaliferous shells ; De Blainville as- 

 sumes that they indicate periods of generation ; but a 

 varix, says M. Dcshayes, is deposited on the earliest for- 

 mation of the shell, and it is quite unnatural to suppose 

 that the animal employs that function immediately on its 

 ejection from the ovary. Other zoologists have imagined 

 that the varices indicate the order of the seasons ; but, 

 repeats M. Deshayes, the Ranella? live in a climate where 

 there is but one season, and the temperature of the waters 

 they inhabit is the same all the year round. It is agreed 

 on all sides that the varices are deposited as a marginal 

 protection to the shell during a period of rest ; but I find 

 nothing beyond conjecture as to the purpose of this pe- 

 riodical rest, the time which elapses between the con- 

 struction of a varix and a renewal of the operation of 

 growth, or between the renewal of growth and the for- 

 mation of another varix. 



Very few alterations have been proposed in the ge- 

 neric appropriation of the Ranella? : Schumacher subdi- 

 vides them by the introduction of the genera Gyrina and 

 Bu/onaria, and Pfeiffer abandons the genus altogether to 

 unite them with the Tritons ; neither, however, of these 

 changes have been adopted. 



The last-published monograph of the genus Ranella 

 by M. Kiener included twenty-seven species ; that num- 



ber I have now the pleasure of increasing to fifty, and 

 of these about fifteen are new to science. 



Species 1. (Mus. Cuming.) 

 Ranella subgranosa. Ran. testa elongato-ovatd, vari- 

 cibus subobtuso-rotundatis ; anfraclibus Ireiter a/igu- 

 latis, ad unguium nodulosis, transversim liratis, /iris 

 numerosis, confertis, subtiliter granulatis ; ceerules- 

 cente-albd, fuscescente vane tinctd et strigatd; 

 aperturd e/ongato-ovali, utrinque canaliculatd ; labro 

 dentato. 

 The subgrained Ranella. Shell elongately ovate, 

 varices rather obtusely rounded; whorls slightly 

 angulated, noduled at the angle, transversely ridged, 

 ridges numerous, close-set, finely granulated ; blue- 

 ish white, variously stained and streaked with light 

 brown; aperture elongately oval, canaliculated at 

 both ends ; lip toothed. 

 Beck, Sowerby, Jun., Conch. Illus., Ranella, f. 18. 



Ranella Beckii, Kiener. 

 Hab. Bay of Manila; Cuming. 



This species may be distinguished by its finely gra- 

 nulated close-set ridges, by its peculiar blue tinge of 

 colour, and by the rounded, spineless character of the 

 varices. 



It was very injudicious of Dr. Beck to give the 

 name of sajgranosus to this shell, when there is already 

 a sraigranosus of Lamarck , still the names are dif- 

 ferent, and I think M. Kiener is not justified in altering 

 them. 



Species 2. (Mus. Cuming.) 



Ranella aliuvaricosa. Ran. testa oblongo-ovatd, de- 

 pressiusculd, varicibus tubercu/is subspinosis promi- 

 nentibus armatis ,• anfractibus leviter angulatis, tu- 

 berculis subspinosis infra unguium bisi riatim armatis, 

 transversim elevato-striatis, inferne liratis, striis 

 lirisque leviter undidatis, stibti/issime granulatis ; 

 albd, rufescenle-fuseo tinctd, varicibus uircis ,■ aper- 

 turd oblongo-ovali, utrinque canaliculatd, fauce pal- 

 lide purpurascente ; labro dentato et sulcata. 



The white-varix Ranella. Shell oblong-ovate, ra- 

 ther depressed, varices armed with prominent 

 prickly tubercles ; whorls slightly angulated, armed 

 beneath the angle with two rows of prickly spines, 

 transversely elevately striated, ridged towards the 



July 1844. 



