BY C. HEDLEY. 389 



the hinder half of the body, the tail slightly projects ; it 

 is flat, without a trace of a mucous gland, and bluntly pointed. 

 The margin of the foot is produced into a slight flange. A 

 pair of grooves running along the median line from the mantle 

 to the muzzle define a row of small tubercles. Right and left, 

 between this median line and the foot edge, there may be traced 

 two indistinct grooves proceeding from the mantle to the lips. 

 Posterior to these the surface is divided into tubercles by small 

 irregular grooves meandering outwards and downwards. Mantle 

 margin simple, unlobed, protruding around the circumference of 

 the shell. Sole without a defined median area. Colour reddish- 

 brown, splashed with black, darkest above ; mantle and sole ashy- 

 yellow. The animal in motion probably resembles Paryphanta 

 husbyi as portrayed P.L.S.N.S.W. (2), ii. pi. xx. fig. 6. 



Shell rudimentary, auriform, thin, opaque, oval, increasing irregu- 

 larly. Colour, without, glossy chestnut shaded to greenish-yellow 

 at the margin, spire tinged with pink ; within, nacreous, gleaming 

 white and purple, columella white. Whorls 2 ; tii'st 1^ embryonic, 

 succeeding half adult, embryonic shell \ of total length, regular, 

 well defined, commencing smooth, afterwards spirally grooved ; 

 adult most rapidly increasing, finger-nail shaped, descending much 

 at the suture, coarsely irregularly transversely wrinkled and 

 faintly spirally grooved. Growth margin sharp yet firm, exhibit- 

 ing no trace of an epidermal fringe. Columella stout, below 

 terminating in a minute double tubercle, above broadening upon 

 the embryonic whorl and excavated for the reception of the 

 columella muscle. Length, 10; breadth, 7 ; height, 2 mm. 



Jaw none. 



Radula strap-shaped, 12 mm. long by 3 broad. Formula, 61 

 rows of 24 : : 24. The central tooth is wanting, and probably 

 many others are missing with it. Here and there in the rachidian 

 cleft (which suggested the generic name) appears a minute, 

 rudimentary and unsymmetrical denticle. From this the four 

 innermost teeth, of a starved and functionless appearance, increase 

 rapidly in size ; the remaining teeth are in bulk nearly equal. 

 The crest of the radula being crushed down by the cover glass, the 



