36 RANELLA. 



Genus RANELLA, Lain. 



In Eanella the tentacles are commonly somewhat closer together 

 than in Triton, and the head is longer and narrower than in 

 Murex and Fusus ; the eyes in some species are nearly basal, but 

 are generally placed about the middle of the tentacles on their outer 

 sides ; the siphon is short and directed upwards ; the foot larger 

 than in Triton, Murex, or Fusus, and considerably dilated both 

 before and behind ; the mantle does not appear to be furnished 

 with limbriated processes as seen in some Murices. In some 

 species the trunk is enormously developed, whilst in others it is 

 not protruded, in the usual condition of the animal. Operculum 

 ovate, horny, with a lateral nucleus and semicircular elements.* 



The species are inhabitants of warm seas, and principally trop- 

 ical : those of the typical group, having winged varices live in 

 deep water, whilst the nodose species forming the sub-genus 

 Lampas, are found at less depth, and prefer coral reefs and rocks. 

 The animal is active in its movements. Eupleura, formerly con- 

 sidered a subgeneric group of Eanella, is now classed with Muri- 

 cinse, on account of the lingual dentition of one of its species.f 



I have retained the generic name Eanella in preference to Bursa, 

 Gyrinium, Bufo, Rana, etc., all of which have priority, but were 

 obscurely published and have never attained general acceptance. 



Mr. Macdonald J thus describes the larval state of Ranella : 



" I next observed a stout little shell, much resembling a Mac- 

 yillivrayia in form, but having the spire more minute and sharply 

 marked, and the whorls beset with epidermic spines, disposed in 

 close spiral lines. The microscopic examination of the animal 

 gave unmistakable proof of its being a Ranella, the lingual den- 

 tition agreeing, at least generically, with my figures and speci- 

 mens. On examining the operculum, which in Ranella, is so 

 very remarkable, exhibiting three successive stages of growth, 

 I found that it was quite of the same character, Only that it had 

 but yet attained the second stage, Finally, on comparing the 

 whole operculum, and the little shell respectively, with the nu- 

 cleus of the operculum and the apex of the shell of an adult 



* Adams and Reeve, Voy. Samarang, 37. 



f For the species of Eupleura vide Vol. 11, p. 157. 



\ Linn. Trans. XXIII, 69. 



