150 



SYSTEMATIC ARRANGEMENT 



below with tubercles, the remaining teeth slender, with a compressed 

 hook, pointed ; in the inner one toothed below, serrulated on both 



Fig. 81.— Teeth of Ziziphinus vulgaris. 



sides, in the middle ones pectinated on each side, in the last obso- 

 lete ; scape slender, simple, furnished before the base with an external 

 spur-shaped process (fig. 81). 



Lingual membrane of Ziziphinus vulgaris elongate, linear, trans- 

 parent. Teeth 00 * 1 • 5 • 1 • 00 ; central square, about as long as 

 broad ; apex rounded, very slightly recurved ; inner lateral teeth 

 5 * 5, thin, half-ovate ; apex rounded, recurved ; central lateral teeth 

 strong, claw- like, compressed, curved, acute ; outer lateral teeth very 

 numerous, hair-like, sinuous, subequal, innermost rather largest, 

 curved at the tip. 



Lateral vibracula of Ziziphinus vulgaris 4 ' 4, the neck-lappets on 

 each side large, subrotund, symmetrical, plain on the edges ; head- 

 lappets none. 



The head-lappets of Ziziphinus Montagui are each split into five 

 short, flattish cilia, fimbriated at the sides ; neck-lappets plain, that 

 on right side largest, and often rolling itself up like a branchial 

 fold. 



Muzzle of Ziziphinus granulatus elongate ; mouth with a pair of 

 oval, horny laminae, and a very short lingual riband passing to the 

 oesophagus ; head-lobes very small, lateral ; neck-lappets two, 

 similar, large, pendent, and sinuated ; lateral vibracula four on each 

 side, partially retractile into a tubular sheath, and in constant 

 motion. — Clark, Moll. 305. 



10. Thalotia. 



Shell conical, turrited, solid, granulated ; axis imperforated ; aper- 

 ture longer than wide ; pillar-lip subtnmcatc, tubercular ; outer lip 

 thickened and crenulated within. Operculum manv-whorled, — 

 Adams, Gen. Moll. 420. t. 48. f. 1. 



Australia; New Zealand. 



1. T. conica. 



