104 GASTROPODA. [Aspidobranchia. 



Sect. 1. PUNCTURELLA, s. str. 



Apex persistent ; the fissure at or near the summit ; the internal 

 plate with or without side props. 



1. Puncturella demissa, Hedley, 1904. Plate 6, fig. 16. 



Puncturella demissa, Hedley, Rec. A.M., v, 1904, 93, f. 19 in text; I.e., vi, 

 289, pi. 54, f. 3-5. 



Shell small, thin but opaque, low-arched, summit posterior, within 

 the margin. Sculpture : Fine incremental threads, scarcely undulated 

 by obsolete radial ribs. Colour white. Anterior slope gentle, arched ; 

 posterior steep, straight. Nucleus persistent, set obliquely, exposing 

 part of 2 spiral whorls. Slit on the summit linear-lanceolate, more 

 than three times longer than broad. Aperture oblong, rather broader 

 in front. Th.e septum drawn down to a third of the length of the 

 shell, completely screening the interior from the slit, thickened at 

 the margin. 



Length, 1-8 mm. ; breadth, 1-2 mm. ; height, 1 mm., type (Hedley). 

 Length, 2*5 mm. ; breadth, 1-5 mm. ; height, 1-5 mm. (Hedley). 



Type in the Australian Museum, Sydney. 



Hob. Foveaux Strait, type (A. Hamilton) ; Snares, in 50 fathoms 

 (Captain Bollons). Australia : 22 miles east of Narrabeen, in 80 

 fathoms (Hedley) ; off Port Stephens ; off Port Kembla, in 63-75 

 fathoms ; Wreck Bay, in 20 fathoms. 



Remarks. The comparative smoothness, persistent apex, narrow 

 fissure, and long septum sufficiently characterize this minute species. 

 The surface is clothed with a rather caducous ochraceous epidermis, 

 disposed in oblong grains. When stripped of the epidermis the white 

 surface of the shell shows no trace of these grains, and would readily 

 pass for a different species. Towards the margin some specimens 

 have broad, shallow, radial undulations (Hedley). 



Genus 6. FISSURIDEA, Swainson, 1840. 



Fissuridea, Swains.. Malacology, 1840, 356. Type: F. pileus, Swains. 

 Lucapina (in part), Ad., G.R.M., i, 447. Cupiluna, Gray, 1857. Glyphis, 

 Carpenter, P.Z.S.. 1856 (1857), 223; not of Agassiz, 1843 : Man. Conch. 

 (1), xii, 175, 202, 203. 



Animal capable of being entirely contained in the shell, resembling 

 Fissurella in external characters. Snout short, ending distally in an 

 oval disc, with the mouth in the centre ; tentacles subulate, with 

 black eyes on little projections at their outer bases ; epipodium consist- 

 ing of a fringe of short filamentous processes altenately larger and 

 smaller, becoming more obsolete posteriorly, where it is marked by 

 little tubercles in place of the filaments. Mantle-edge smooth or 

 papillose, usually rather broad. Central tooth of the radula wide. 



Shell ovate, conical, the orifice in front of the middle. The apex 

 spiral, inclined backward in the young, wholly absorbed in the adult. 



