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MONOGRAPH OF THE GENUS 

 APORRHAIS. 



Char. Gen. Molluscum marinum ; testa turrita, fusiformi ; 

 apertura sub-quadrata ; labio externo aetate dilatato, magno, antice 

 et postice prope canales undatim emarginato ; canali anticd 

 rostrato, sub-foliato ; labio interno crasso, canali postico. 



DESCRIPTIONS. 



Sp. 1. A. pes-pelecani. (pi. v. f. 3, 4.) Linn. 



T. turrita fusiformi, anfractibus angulatis, nodulosis ; apertura 

 sub-quadrata ; canalibus duobus, rostratis, sub-complanatis ; labio 

 externo crasso, bilobato. 



A well known species found in Great Britain and the 

 Mediterranean. 



2. A. PES-CARBONIS. (pi. V. f. 1) ? 



T. quam A. Pes-Pelecani magis tenui; canalibus elongatis; labio 

 externo trilobato. 



A thinner and smaller species, with the beaks of the canals 

 narrower and more lengthened, and the outer lip divided into 

 three digitations. Mediterranean. 



3. A. OCCIDENTALS, (pi. V. f. 2.) 



T. turrita, concentrice plicata, spiraliter striata ; canalibus 

 brevibus; labio externo unilobato. 



Sr,ell turriterl, with longitudinal ribs, spirally striated; canals 

 short; outer lip with one uigitation. 



MONOGRAPH OF THE GENUS 

 ROSTELLARIA. 



Char. Gen. Molluscum marinum ; testa fusiformi, antice in 

 canalem rostratum desinente ; apertura ovali ; canali postico 

 partem spirse decurrente ; labio interno crasso ; labio externo digi- 

 tato ad canalem emarginato ; operculo corneo, unguiculato. 



