MOLLUSCA FROM JUAN FERNANDEZ AND EASTER ISLAND 235 



new genus Pacificella [see below]," which, however, may perhaps be made the 

 type of a distinct family) may be given as follows: — 



Radula (fig. 14) achatinelloid but its front part reflected and ring-like 

 closed ^ genital organs (fig. 15) situated above the retractor oculi^; penis with 

 a well developed appendix and a bifid retractor inserting with the one part the 

 penis proper, with the other the appendix; spermatheca with a very long 

 stalk; albuminiparous gland well developed. Viviparous; oviduct with many 

 embryoes. 



The most important conchological character of Tornatellinidae is, according 

 to PiLSBRY, the presence of a parietal lamella in the aperture. This is a feature 

 constant in Toynatellina proper, but is wanting in Fernandezia, which proves, 

 however, to be very closely related to Tornatellina. There exists, indeed, two 

 species, which are variable in this respect inasmuch as they lack a parietal 

 lamella in adult stage but possess it as young. This fact proves that the 

 anatomical characters alone are available for constituting natural groups and 

 judging affinities of the Pacific land mollusca in question. 



Tornatellina (Beck) Pfeiffer 1842. 



PiLSBRY, in his excellent Monograph of Tornatellinidae, (191 5), states that 

 »the type of Tornatellina is a little-known species from a peripheral locality 

 (Juan Fernandez))). This type is T. bilamellata Anton, and to the same genus 

 a great many species have been allotted, scattered over the whole Pacific, 

 though the interrelations of them, as PiLSBRY holds forth, have been totally 

 undetermined on account of the entire lack of anatomical data. I am inclined 

 to the opinion that they must be further divided, the Pacific forms probably 

 being, to a great extent, congeneric with the Easter Island Pacificella variabilis, 

 described below, and the Juan Fernandez forms solely constituting the genus 

 Tornatellina. The anatomical characters of this genus are deduced from an 

 examination of the typical species T. bilamellata and prove to coincide with 

 those of Fernandezia, though there is a much longer appendix of the vestigial 

 penis, and that is simply cylindrical and destitute of the accessory sac, charac- 

 teristic of the other genus. 



Tornatellina bilamellata Anton. PI. 9, fig. 36 (a variety). — The 

 specimens before me agree in size as well as in habitus and dentition with the 

 figure given by KiJSTER (Conchyl. Cab. I: 15, Pupa, pi. 18, figs. 3 — 5), the identity 

 stated by Pfeiffer and Smith, who also record it from Juan Fernandez, thus 

 being verified. Anton's locality of the typical specimen, »Opana», is certainly 

 a mistake (cf. PiLSBRY 191 5, p. 139). 



Localities. Masatierra, Aug. 1917; Pangal, on ferns and under leaves, 

 many shs., max. h. 7, br. 3,2, and h. 6,5, br. 3,3, and h. 6,2, br. 3,3; all with 8 



^ In Achatinellidas the radula is open throughout. 



' In AchatineUidas the eye retractor (the right in dextral, the left in sinistral animals) is 

 situated above the penis according to an examination of Achatinella livida Swainson from 

 Honolulu, Eugenie Exp. 1852 (Riksmus.). 



