550 



formem. Pes expansus, antice angustatus, rotundatus, postice 

 latus, truncatus, lateribus valde dilatatis, natantibus. 



Testa subcylindrica, elastica, convoluta, ultimo anfractu in 

 suturii aliis soluto ; spira distiucta, anfractibus canaliculatis, vertice 

 obtuso; apertura postice augustata, antice effusa. 



Head elongated, wide and bifid anteriorly, narrow posteriorly. 

 Eyes none. Mantle with a fimbriated edge projecting through the 

 slit in the spire. Foot expanded, narrow and rounded anteriorly, 

 posteriorly broad and truncated; the sides greatly dilated and 

 forming swimming lobes. 



Shell cylindrical, elastic, convoluted, the last whorl separated in 

 the suture from the others ; spire distinct, whorls channelled ; 

 apex obtuse; aperture narrow, posteriorly contracted, anteriorly 

 effuse. 



Akera, Midler (not Cuvier). Eucampe, Leach. Vitrella, 

 Swainson. 



Genus 7. Scaphander,, Montfort. (Animal, pi. cxix. f. 5. 

 Shells, Bulla, sp. 38-42. pi. cxxi. f. 47-51.) 



Animal ut in Bulla. 



Testa ovalis ; spira subocculta, truncata. Apertura amplissima, 

 testa longior ; antice valde dilatata, integerrima ; postice coarctata, 

 excisa ; labium externum acutum. Margo cochleae spiraliter ma- 

 nifeste convolutus usque ad originem spirse. 



Animal as in Bulla ? 



Shell oval ; spire somewhat coucealed, truncated. Aperture 

 very wide, longer than the shell, anteriorly greatly dilated, entire, 

 posteriorly contracted and channelled ; outer lip acute. Margin 

 of the shell distinctly spirally convoluted as far as the commence- 

 ment of the spire. 



Arrula, Schum. Charta, Martini. Bttllaa, Roissy. 



Genus 8. Bulla, Klein. (Animal, pi. cxix. f. 6. Shells, 

 Bulla, sp. 43-55. pi. cxxii. and cxxiii. f. 59-80.) 



Corpus oblongum. Caput latum depressum, lobis posticis 

 duobus ; oculi sessiles in medio capitis. Pallii dextra pars 

 carnosa, pedem longe superans; sinistra pars tenuis, adhserens. 

 Pes brevis, subquadratus, lateribus antice reflexis, anteriorem 

 partem testae vix tegentibus. 



Testa ovato-globosa, convoluta ; columella nulla ; spira immersa, 

 tubulosa; apertura longitudine testa;, margine externe acuto. 



Body oblong. Head broad, depressed, with two posterior lobes. 



