Genera of Terrestrial Mollusca^ etc. 205 



umclla callosa, aperta, appondiciila dilatata, torta supcnio 

 muuita," adding in a footnote, "Forma porsimilis priDcodcnti 

 (^S. depressa Rang), at bono distincta colnmella appendice 

 torta qnasi dnplicata, spira snbpapillatim proniinula ct peri- 

 phcria magis regnlari." Tliis appendage is shown in our 

 figure (pi. ix, fig. 6) of Rawson's ap2)endicalata. 



V. Martens (Malak. Blatt., 1868, p. 183) described 8uc- 

 cinea {Pellicula) convexa, to the dentition of which by 

 Ileynemanu we have already referred, giving also (plate ix, 

 figs. 12-14) copies of his figures.* One of the characters 

 of this species is said to be by its author, "paries aperturalis 

 appendicula parva, plicie-formi nnuiitus." 



With respect to the validity of his species, v. Martens 

 adds a note to the following effect, — jS. deprexsa Rang, as its 

 name implies, differs from our species by being less arched. 

 Pfeiffer writes that P. convexa is by no means the same as 

 his 8. appendicidata. If the latter bo identical with dejyressa 

 as Fischer maintains, then Rang's figure is entirely faulty, 

 the most essential character, the process on the columella, 

 being overlooked. 



A comparison of the figures presented on plate ix, will 

 show that the Pellicula depressa of Fischer has a ribbed jaw 

 (fig. 4), and does not belong to the 8uccininai,\ while Pellic- 

 ula convexa v. Martens is elasmognathous, like 8uccinea 



(fig. 14). 



It seems to us that 8. depressa of Fischer must be treated 

 as the type of Pellicula, while 8. convexa belongs to 

 Omaloni/x. 



Albers (ed. 2) does not include in Omalonyx or other 

 group 8. depressa or 8. aptpendiculata, mentioning them only 

 in a remark of the following purport : — 



*v. Martens (Zool. Record, 1808, p. 492), referring to Ileynomann's figure, says 

 " proving that Pellicula is not geiicrically iliHtinct from Succinea."—a proposition in 

 which wo do not concur. II. & A. Adams (Genera, II, 508) inconsiderately remark tiiat 

 Pellicula Fisclier is syn. of Helisiga, and founded upon //. depressa Fischer, a new spe- 

 cies of tliat genus. 



t Miircli (Jour. Conch. 1805, p. 384) places Pellicula in his section Odontognatha. 



