hardly to be distinguished from the later growth, obtuse; anterior side of shell slightly produced, rounded, posterior side broadly convex; the whole of the valves concentrically finely striate. Ligament inset. Left valve with a straight lamellar upper cardinal, and below and slightly in front of it a curved stouter tooth. In the right valve the two cardinals are united, forming an oblong squarish tooth with three denticulations on the lower margin. Laterals smooth. Fig. 5 illustrates the cardinal teeth of the two valves. Length, 5 mm.; height, 4¼ mm.; diam., 2¾ mm. Umbo 3 mm. from anterior end. The indices are—iii. = 85; vii. = 55; x. = 60.

Fig. 5

This is no doubt the same as S. lenticula, Dunker, as Hochstetter obtained the specimens from the lakes Rotoiti and Taupo, and I consider it as a synonym of S. novæ-ze-landiæ.

(2.) Lake Taupo (Stat. 4—Dredged with weeds in 20 ft., and from bottom of coarse pumice in 100 ft.).—Four specimens of straw colour, the nepionic shell rather distinct, but otherwise not differing from the typical form. Right valve with two minute cardinals, the anterior oblong, the posterior short, triangularly oval, elevated. Left valve with two minute teeth, broadly rounded behind, pointed at the anterior end, one in front of the other. Fig. 6 shows the form and position of the cardinals. Length, 4½ mm.; height, 4 mm.; diam., 2½ mm. Umbo 2¾ mm. from anterior end. Indices—iii. = 84–89; vii. = 56; x. = 61.

Fig. 6

(3.) Lake Taupo (Stat. 34—With weeds from 20 ft. to 80 ft.).—Six small specimens, a little more oval and compressed, but otherwise the same as the examples from Stat. 4. Length, 4 mm.; height, 3 mm.; diam., 1¾ mm. These are the dimensions of Dunker's S. lenticula. Indices—iii. = 75; vii.—44.

(4.) Lake Waikaremoana (Stat. 33—Dredged in 10 ft. to 20 ft.).—There are twenty-three small to minute specimens. The larger examples are yellowish-grey, the small ones straw-colour. In the right valve there are two lamellar cardinal teeth meeting at an obtuse angle; in the left valve there is one crescent-shaped

Four specimens were measured—Length, 2¾–5 mm.; height, 2½–4 mm.; diam., 1¼–2½ mm.: and the mean indices are—iii. = 83; vii. = 48; x. = 59.

These specimens are very much like those I collected in the River Avon, Christchurch.

(2.) Lake Waikare (Stat. 29F—From weeds in 1½ ft. to 2 ft.).—Four specimens, dead when collected. They do not differ much from those of Stat. 29, except being slightly more globular. The dimensions of three specimens measured are—Length, 5 mm.; height, 4½ mm.; diam., 3¼ mm.; umbo 3 mm. from anterior margin: length, 4¼ mm.; height, 3½ mm.; diam., 2¼ mm. umbo 2½ mm. from anterior margin: length, 3 mm.; height, 2½ mm.; diam., 1½ mm.; umbo 1¾ mm. from anterior margin. The mean indices are—iii. = 85; vii. = 56; x. = 58.

(3.) Lake Wakatipu (Stat. 17—Dredged with weeds in 20 ft. to 100 ft.).—One minute specimen, rounded, yellowish-white, subequilateral. Length, 2¼ mm.; height, 2 mm.

This small specimen has the aspect of a Sphærium, but the nepionic shell is so distinct that I prefer placing it in Corneocyclas for the present. I tried to separate the valves, but could not do it without running the risk of breaking the valves. Without ample material, and especially examining the living animal, it is impossible to be quite certain about its generic position.

(4.) Lake Wakatipu (Stat. 34—Dredged in 10 ft. to 30 ft.).—One adult and four young specimens. The adult is light-brown, the nepionic shell distinctly limited; the young examples are grey to yellowish, more inequilateral and tapering in front. The dimensions of two specimens are—Length, 5¼ mm.; height, 4½ mm.; diam., 2½ mm.; umbo 2¾ mm. from anterior end: length, 3½ mm.; height, 1¾ mm.; diam., 1½ mm.; umbo 2 mm. from anterior end: and the mean indices are—iii. = 83; vii. = 46; x. = 55.

There is one specimen, covered with a black coating, which is suborbicular, much compressed, inequilateral, with inconspicuous beaks, the anterior side broadly rounded. The dimensions are—Length, 4 mm.; height, 3¼ mm.; diam., 1½ mm.; umbo 2½ mm. from anterior end: and the indices are—iii. = 81; vii. = 38; x. = 62. I have seen similar abnormities amongst specimens I collected in the River Avon.

(5.) Lake Manapouri (Stat. 13—Dredged in shallow water near the shore).—Three young specimens, which are at once recognised as being Corneocyclas, being more inequilateral, compressed and attenuated anteriorly than adult specimens. Had I not seen the same forms from other localities, collected together with adult examples, I might have been inclined to consider