232 REV. H. B. TRISTRAM ON GUATEMALAN MOLLUSKS. [May 28, 



27. Planorbis tumidus, Pfr. 



28. Planorbis wyldi, nov. spec. 



T. discoidea, tenuis, turgida,fusco-cornea, hand nitens, aspere striata, 

 supra profunde umbilicuta, subtus plano-concava ; anfract. 5, ro- 

 tundati, modice crescentes ; apertura obliqua, sublunaris, subtus 

 valde depressa, supra dilatata. 



Diam. niaj. 15, miii. 11 niilL, alt. 8 mill. 



Hab. Lake of Duenas. 



29. Planorbis duenasiantjs, nov. spec. 



T. discoidea, tenuis, albido-cornea, tenerrime striata, pellucida, hand 

 nitens, supra concava, depressa, subtus plana; anfract. 6, lente 

 accrescentes, ultimus acute sed minutissime carinatus ; apertura 

 obliqua, rhomboideo-compressa. 



Diam. maj. 7^, min. 6^ mill., alt. 1 mill. 



Hab. Lake of Duenas. 



30. Planorbis. 

 Undescribed iu coll. Cuming. 



31. Segmentina donbilli, nov. spec. 



T. compressa, albido-cornea, tenuiter striata, superne et infra simi- 

 liter vmbilicata, convexiuscula ; anfract. 5, lente accrescentes, 

 rotundati ; apertura obliqua, rotundata ; perist. inivs albo-labia- 

 tum, denies 6 intus ostendens, quatuor in pariete externa, duo in 

 par. interna. 



Diam. maj. 9, min. 7 mill., alt, 2| mill. 



Hab. Lake of Duenas. 



32. Melampus fasciatus, Chemn. 

 Hab. Salt marshes on the coast. 



33.Adamsiella osberti, nov. spec. 



T. rimato-perforata, turrita, integra, pallide fulva, longitudinaliter 

 conferte striata, fasciis 5 vel 6 interruptis rubris ornata ; spira 

 regulariter turrita, apice plerumque abrupta -, anfr. 6, ultimus so- 

 lutus ; apertura verticalis, rotunda ; perist. duplex, internum cas- 

 taneum, breviter porrectum, externum dilatatum, horisontaliter 

 patens, rufescens, superne angulate productum, ad anfr. penul- 

 timum subexcisum. 



Long. 12, diam. 5-6 mill. 



34. Cistula trochlearis, Pfr. 



35. Chondropoma rubicundum, Morelet. 



36. Megalomastoma simulacrum, Morelet. 

 Described by Morelet from Costa Rica. 



37. Cyclophorus ponderosus, Pfr. 



38. Cyclophorus translucidus. Sow. 



