Gadinia.] GASTROPODA. 603 



horseshoe-shaped and broadly open in front. There is a small mus- 

 cular scar in front of the left end of the adductor-scar. 



Distribution. Mediterranean, west coast of Africa, Mauritius, west 

 coast of America. Australasia. 



1. Gadinia nivea, Button, 1878. Plate 24, fig. 9. 



Gadinia nivea, Hutt., J. de Conch., xxvi, 1878, 36 ; T.N.Z.I., x, 290, xv, 

 144 ; M.N.Z.M., 37. 



Shell ovate, conoidal, generally depressed, radiately ribbed, apex 

 rather posterior. Sculpture consisting of about 40 subequal narrowly 

 rounded straight riblets. some of which do not extend to the summit ; 

 concentric growth -periods are mostly present, and very often pro- 

 ducing prominent ridges. Colour white, light-pinkish towards the 

 margin ; interior white, the margin light pink. Apex subcentral to 

 nearly marginal, small and distinctly uncinate in well-preserved 

 specimens ; anterior and side slopes convex, posterior slope straight, 

 concave, or lightly convex. Interior shining, the adductor-scar and 

 siphonal groove distinct. Margin very slightly crenulate. 



Diameter, 18 mm. ; length. 20-5 mm. ; height. 3-7-5 mm. 



Anatomy. Hutton. T.N.Z.I.. xv. 144. pi. 17, f. S-V. 



Dentition. Formula of the radula 150 x 60 + 1 + 60, transverse 

 rows forming an angle of about 90, re-entrant anteriorly. Central 

 tooth with 4 minute denticles ; laterals about 21, each with a long 

 pointed cutting-point and a small denticle on the inner side. Mar- 

 ginals with a long median cutting-point and a small denticle on the 

 inner side. 



Type in the Otago University Museum, Dunedin. 



Hob. Coast of Otago (type) ; Whangarei (C. Cooper) ; East 

 Cape ; Stonyhurst (F. Suter) ; near Taumaki Island, in 10 fathoms, 

 small dead shells (Captain Bollons) ; Chatham Islands. Living on 

 rocks between tide-marks, and in roots of U Urvillcea utilis ; not 

 common. 



Fam. LYMNOEIDJE. 



Limnceidce, Broderip. 



Animal with a short broad muzzle, dilated at the end ; mouth 

 with a horny upper jaw ; tentacles flattened or filiform, with the 

 eyes sessile, at their inner bases. Mantle-margin variously modified ; 

 respiratory orifice at the right side. Foot flattened, lanceolate, or 

 ovate. Excretory orifices on the left side of the neck. No inferior 

 pallial lobe. 



Shell thin, dextal. with prominent spire and oval aperture. No 

 operculum. 



Their distribution is world-wide. They live in lakes, ponds, pools, 

 ditches, and. though not so abundantly, in rivers ; occasionally they 

 are found in brackish waters. They crawl on the mud and stones at 

 the bottom, or on water-plants, and in warm sunny weather ascend 



