540 Rev. L. Guilding on the Zoologi/ of 



Genus. Ceratodes. Guild. 

 Ampullaria. Sow. 

 Planorbis. Lam. 



Char. Gen. 

 Animal AmpullaricB simile, at siphones cervicis minorcs et 

 breviores. Penis apice supra verrucam deflexo, &c. 



Testa dextera, * discoidea, tenera, epidermide tenuissima 

 vestita, facie Planorbis, longitudinaliter plicatula ; umbilicus 

 maximus profundus, (incola serpente) sinister, centralis. Spira 

 valde depressa, vix prominula ; anfractibus omnibus dextrorsum 

 conspicuis. Operculum jittipidlaria, at reniforme. Reritrema 

 simplex. Columella evanida. Columellarium parvulum. Apertura 

 semirotundato-lunata, ab axe remotissima. 



Typus genericus, Planorbis cornu arietis +. Lam. 



Ceratodes fasciatus. Guild. 



Cer. flavescens, nigro marmoratus : sole^ pallida, nigrescentc 

 maculata : operculo fusco, subtus castaneo. 



Testa flavescente pallida, atro-castaneo fasciata : spira apice 

 rufescente, saepe corrosa : apertura crocea. 



Ampullaria cornu arietis. Sozo.^ Gen. of Shells. 



Planorbis cornu arietis. Lam.^ vi. pars 2. p. 152. 



Lister. Conch, tab. 136. f. 40. male. 



Var. a. pulchrior, fasciis crebris, apertura^ nebula purpurea. 

 Animal pallidius, rufescente flavidura, nigro pictum, solea palli- 

 diori immaculata. 



Var. /3. fasciis paucis latioribus. 



Habitat varietate multiplici in fluviis Americae aequinoctialis, 

 satis frequens. 



Desc. Respiratorium diaphanum, amplum, fuliginosum. 

 Abdomen spirale. Cauda cinereo-livida, pallido reticulata. Pal- 

 lium pallidum, flavido reticulatum, marginis superioris glandibus 

 fasciaeformibus. Penis flavidus. 



* The shell, when placed with the spire upwards, will not warrant us in 

 calling it, with Lamarck, a sinistral species. 

 + Nomina composita vituperanda, expellenda. 



