GASTROPODA. [Pulmonata. 



2. Thalassohelix Laingi, Suter, 1905. Plate 25, figs. 5, 5a, 56. 

 Flamm-ulitta (Thalassohelix) Laingi, Sut., J. Mai., xii, 19, pi. 5, f. 1-S. 



Shell globosely depressed, semitransparent, smooth, imperforate. 

 Sculpture consisting of very fine close-set lines of growth, which are 

 crossed by numerous microscopic spiral lirae, more distinctly visible 

 on the base. Colour rufous-horny, whitish round the umbilical region. 

 Epidermis thin, slightly shining. Spire but little elevated, conoidal. 

 Protoconch of 1| obtuse whorls, which are faintly radiately striate, 

 and show indistinct microscopic spiral lines. Whorls 4, the last rapidly 

 increasing, flatly convex, broadly rounded at the periphery, and slightly 

 impressed in the centre of the base. Suture impressed. Aperture 

 oblique, broadly lunately oval. Pn-ixtome simple, straight. Outer Up 

 rounded ; basal margin and inner lip slightly arched ; the latter is 

 strongly callous above and reflexed over the umbilical region ; a 

 broad thin callus unites the converging margins. There is no um- 

 bilicus, not even in the young stage. 



Diameter Maj.. 14 mm. ; min., 11-5 mm. : height, 9 mm. 



Animal of yellowish-brown colour, with a black band and spots on 

 the mantle, distinctly visible through the shell at the periphery. The 

 caudal pore is very distinct, surrounded by a number of roundish 

 papillae. 



Jaw arcuate, thin and fragile, composed of exceedingly fine vertical 

 lamellae. ^ 



Radula (Plate 1, fig. 9) has the formula" 28+7+1+7+28. 

 The central tooth has a mesocone extending a little beyond the 

 base, and 2 minute ectocones. The lateral teeth are very similar 

 to the central ; the transition teeth show the entocone and mesocone 

 fused together into one. a small ectocone being left. The marginals 

 have apparently only the mesocone left, but there is on most teeth 

 a minute ectocone present, which is sometimes split up into two. 



Reproductive organs simple. The vas deferens enters the distal 

 end of the sac of the male organ exactly at the place where the re- 

 tractor muscle is attached ; the vrv^r is covered with rugosities of 

 irregular shape. 



Type in my collection. 



Hab. Long-wood Range, near Otautau, Southland (R. M. Laing). 



3. Thalassohelix propinqua, Hutton. 1883. Plate 9, figs. 1, In. II. 



Thalassia (?) propinqwt, Hutt.. T.N.Z.I., xv, 1882 (1883), 137; xvi, 203. 

 Gerontia (Thalassohelix) propim/nu, Hutt. : Pilsbry, Man. Conch. (2). 

 viii, 72, pi. 22, f. 55-57. Thol/i.^ohelix propinqua, Hutt. : Hedley and 

 Suter, P.L.S. N.S.W. (2), vii, 636. Flammulina (Thalassohelix) pro- 

 pinqua, Hutt. : Suter, J. de Conch., xli, 257. 



Shell depressed, striated, narrowly umbilicated, thin, translucid. 

 not shining. Sculpture consisting of 'exceedingly fine and close micro- 

 scopic spiral stria? on the protoconch, the succeeding whorls rather 



