HORN EXPEDITION—MOLLU9CA. 
207 
Succinea interiopis, Tate. (Plate XTX., Fig. 21.) 
Reference—Trans. Roy. Soc. S. Aust., vol. xviii., p. 191, 1894. 
Shell oval-elliptical in outline; test thin, pellucid, shining, yellowish or 
reddish-horny, raised into folds of growth and ornamented with microscopically- 
reticulate strim. Whorls four; spire elongated, rather acute, its whorls mode¬ 
rately convex in the posterior-third, thence gradually sloping to the anterior 
suture, being much constricted anteriorly ; last whorl moderately conve.x, some¬ 
what attenuate at the base. Aperture oblique, oval, scarcely acuminate posteriorly, 
its length two-thirds that of the shell ; peristome thin, its margins connected l)y a 
thin callous deposit, colurnellar margin feebly reflected posteiaorly. 
Dime7mons. —Length, 17 ; greatest and least diameters, 9-25 and 6’5; length 
of aperture, IPS ; greatest width of aperture at y’jths of the axial length from the 
front. 
Localities .—banks at Illara Water, Laurie’s Creek, Carmichael Creek, 
Redhank, Palm Creek, and in the rejectamenta of the Finke River at Crown 
Point. Also “ at Eversham, a station due west from Rockhampton towards the 
South Australian boundary,” communicated by Dr. Cox. 
I cannot reconcile this Succinea to any of the described species; it, however, 
closely approximates to S. scalariiia, with which it agrees in dimensions as set 
forth in the subjoined table, but the last whorl is more attenuate and not so 
convex, the spire is shorter and narrowei’, the shell is nearly twice the dimensions, 
whilst two thousand miles intervene between their respective habitats. 
PtELATivE Measurements.. 
Shell. 
Aperture. 
« 
Length. 
Maximum 
Width. 
Minimum 
Width. 
Length. 
Width. 
Sicccinea infer ion's 
Succinea scalarina 
100 
100 
54- 4 
55- 2 
39 
42 
66-2 
G8-3 
41 
42 
