Isidora.] (JASTROPODA. 617 



Genus 2. GUNDLACHIA, PfeifTer, 1849. 



Gundlachia, Ph., Zeitschr. fiir Malak., vi, 1849, 98. Type: G. ancylt 

 formifs, Pfr. 



Animal large ; foot oval ; tentacles short, compressed, subtruncated 

 at the apex, dilated at the base and outer side ; eyes at the inner side 

 of the bases. Jaw filiform. Radula with the central tooth bicuspid, 

 laterals bicuspid, and marginals multicuspidate. 



Shell thin, ancyliform, non-spiral, obliquely conical ; apex in- 

 clined back-wards, basal side two-thirds closed with a flat horizontal 

 lamina ; aperture anterior, horizontal, semicircular. Young shells 

 without a septum, ancyliform. 



Distribution. America, Antilles. Australasia. It is an inhabitant 

 of fresh-water streams and ponds. 



f- 



Fossil in the Tertiary. 



KEY TO SPECIES. 



A. Shell conical, oval, sides convex, apex at the posterior third of 



length . . . . . . . . . . . . Lttcusi. 



B. Shell depressed conoidal, oblong, sides subparallel, apex at the 



posterior sixth of length . . . . . . . . neozelanica. 



1. Gundlachia Lucasi, Suter, 1905. Plate 24, fig. L'O. 



Gundlachia Lucasi, Suter, T.N.Z.I., xxxvii, 1904 (1905), 250, f. 10, 10a, 



Shell obliquely conical, thin, semitransparent, horn-colour, covered 

 by a blackish coating. Apex inclined to the right, situated at the 

 posterior third of the length ; convex anteriorly, slightly concave 

 on the posterior slope ; a few concentric lines of growth. Aperture 

 oval ; peritreme sharp, extremely fragile. The shells hitherto ob- 

 tained have no wplum, being in the Ai)ctjlns stage of development 

 only. 



Length, 3 mm. ; breadth. 2 mm. ; height. 1 mm. Length, 4 mm. ; 

 breadth, 2| mm. ; height, 1| mm. 



Dentiti-tiii and jaw the same as in the next specie*. 



Tyfif in my collection. 



Hob. Lake Waikare (K. Lucas) ; Inglewood. 



U. Gundlachia neozelanica, Suter, 1905. Plate 24, figs. 26, 26a. 



Gundlachia neozelanica, Suter, T.N.Z.I., xxxvii, 1904 (1905), 258. An- 

 ci/lus sp., Suter, J. de Conch., xl, 1892, 248. Ancylus lasmanicus, 

 f.-Woods : Suter, P.L.S. N.S.W. (2), vii, 624 ; not of T.-Woods. Gund- 

 lachia sp., Suter, T.N.Z.I., xxvi, 122, pi. 14, f. 1-5 (jaw and teeth cf 

 radula) ; Suter, P.L.S. N.S.W. (2), viii, 486 ; Hedley, I.e., 505, 507, 511, 

 I>1. 24, f. 12-15 ; Suter, J. de Conch., xli, 229. 



Shell depressed conoidal, oval - oblong, the sides straightened, 

 subparallel, thin, semitransparent, horn-colour, with a blackish-green 

 coating. Apex a little inclined to the right, situated at the posterioi 

 sixth of the length, flatly convex anteriorly ; concentric lines of 

 growth at regular intervals. Interior light brown, shining. Aperture 



