92 GASTROPODA. [Aspidobranchia. 



the last whorl descends much more rapidly than in typical brevis, 

 whilst the earlier whorls are smaller. This combination gives an 

 entirely different appearance to the shell, which is further strengthened 

 by the fact that the fasciole is very little longer than the foramen. 

 Operculum thin, horny, multispiral. Colour cream ; dead shells pure- 

 white. Measurement of a large specimen the same as the type of 

 S. brevis, Hedley. (Iredale.) 



Type in the Canterbury Museum, Christ church. 



Hob. Sandfly Bay, Otago Peninsula (type) ; Lyall Bay. 



I have not seen this shell. 



Fam. HALIOTID^E, Fleming. 



Animal with a fleshy foot, a fleshy epipodial ridge fringed with 

 cirri, a frontal veil connecting the short eye-stalks ; spire of the visceral 

 mass much reduced ; the mantle-slit along the row of holes, branchial 

 cavity containing a gill on each side of the slit, the right being the 

 smaller ; no operculum. 



Shell nacrous, spiral, the. spire small, body-whorl very large and 

 depressed, having a row of round or oval holes along the left side, 

 aperture very large, occupying nearly all the lower face, columella 

 (properly speaking) absent, the spire being open in the middle, seen 

 from below ; but the columellar margin is produced into a flattened 

 spiral plate. Muscle - impression horseshoe - shaped, the left branch 

 narrow, inconspicuous, inside the columellar plate, the right branch 

 very large, rounded, situated in the middle of the aperture. 



A few fossil forms not differing materially from the Recent ones 

 have been discovered in the Pliocene and Miocene, and one in the 

 Upper Cretaceous of Germany. The centre of distribution of Recent 

 species is in the Australian and adjacent seas. Only one species is 

 found on the east coast of North America. 



All of these molluscs are rock-lovers. The shells are much used 

 as ornaments, for the manufacture of pearl buttons, buckles, and in- 

 laying. Fine green pearls may be sometimes found under the mantle. 

 The animal is used as bait for catching crayfish, and is sometimes 

 used for food. 



Genus 1. HALIOTIS, Linnteus, 1758. 



Haliotis, Linn., Syst. Nat., ed. x, 1758, 779. Type : H. tuberculata, L. 

 Padottus, Montfort, Conch. Syst., ii, 114. Sulculus, Ad., G.R.M., i, 443. 



Animal with a short, broad muzzle ; tentacles subulate, with the 

 eyes on stout cylindrical peduncles at their outer bases. Foot 

 moderate, not grooved, and produced posteriorly. Radula with a 

 subpentagonal central tooth, constricted in the middle ; the 5 laterals 

 are large, unequal in shape ; uncini numerous. 



Shell oval or oblong, nacreous ; spire small, much depressed ; 

 suture well marked ; aperture with continuous borders ; columella 

 border broad, compressed, and arched ; outer margin very oblique ; 



