of Britlsli MoUusca. 339 



que i'ai recucillic en Algerie. C'est dans la collection do cot 

 amateur que Pt'citTcr la vit et la doorivit.' " 



254. Succinea oblonja, Drapaniaul. 



B. DiTU EM ATA. 



Fani. 7. Oncidiidae. 



Genus Oncidiella, Gray. 



255. Oncidiella celtica (Cuvier). 



The yonnp: of this species in its larval state is furnished 

 ■with a shell which is afterwaixls cast off. 



The systematic position of the Oncidiidae has been much 

 disputed. Bergh *^ after reviewing the varied opinions of 

 authors, sums up his views thus : — ^'The Onchidia agree with 

 the Pidmonata in the structure of the nervous system^ in the 

 existence of a lung and of a parenchgmatous kidney, in the 

 presence of the peculiar pedal gland, and in various peculia- 

 rities of the generative system. From a tolerably extensive 

 knowledge of the so-called Nudibranchs I cannot but regard 

 the Onchidia as pretty widely separated from them. On the 

 contrary, they branch off from the Pulmonata ; they are Pul~ 

 monata which have adapted themselves to an amphibiotic or 

 marine mode oflifey 



Suborder II. GEIIYDROPIIILA. 



Fam. 8. Auriculidae. 

 Genus 1. Carychium, O. F. Miiller. 



256. Carychium minimum^ Midi. 



Genus 2. Alexia, Leach. 



257. Alexia myosotis (Drap.). 



258. Alexia denticulata {^lon\.)^Melam2-)us myosotis, var. 

 ringens, JefFr. 



Genus 3. Leuconia^ Gray. 



259. Leuconia hidentata (Mont.). 



Var. alba, Turton. 



* Bergh, 'Morpliologisches Jahrbuch,' Bd, x. p. 172 ; translated, Aun. 

 & Mag. Nat. Hist. ser. 5, siv. 1884, p. 259. 



