2 
INTRODUCTIO . 
Cl. Deshay es 1830 (Encycl. meth. III. p. 552. Tabl.) 
designationem Helicineorum (Les Helicines) pro tertia Pul- 
mobranchiatorum familia, genera: Cyclostoma , Strophostoma 
et Helicinam complectente, proposuit. 
Cl. Wiegmann 1832 (Handb. d. Zool. p. 527. Ed. 
sec. p. 555.) ordinem nostrum tamquam familiam Pulmona- 
torum nomine abbreviato Operculatorum tractavit, genera ei 
adscribens: Cyclostoma , Helicinam , Steganotomam et Pa- 
pin am. 
CL Anton 1839 (Verzeichn. p. XIII. 52.) nomine Cy- 
cle stomace or am familiam designat , praeter Cyclostoma et 
* Helicinam etiam Littorinam minus bene complectentem. 
Cl. Hartmann 1840 (Erd- u, Siissw. Gast. Syst. 
Uebers.) nom. Pseudobranchiatorum seu Teleogeophilorum 
genera Choristoma , Pomatiatem et Cyclostoma conjunxit, 
cui section! Helicina certe adscripta fuisset, si generum non 
in Europa obviorum mentio facta esset. 
Sectio Pneumonobranchiatorum operculatorum a Cl. 
Gray 1840 (in Turt. Man. Ed. sec. p.273) proposita, etiam 
nostro ordini congrua est, etsi illo loco solum familia Cyclo- 
stomidarum tractata sit. 
Cl. D’Orbigny 1841 (Moll. Cub. I. p. 199. 236.) in 
prima familia Pectinibranchiatorum dioicorum Cyclostomidas 
admittit, cui genera: Odontostoma (ad Helicea potius refe- 
rendum), Helicina , Cyclostoma et Strophostoma subjunguntur. 
CL Peeve 1842 (Conch, syst. II. p. 90.) nomine Cyclo- 
stomaceorum eundem ordinem designavit, admittens inter ejus 
genera praeter Pupinam , Cyclostoma et Helicinam etiam 
Trunc atellam ; quarn methodum secuta est CL A. Catlow 
1845. (Conch. Nom. p. 168.) 
CL Sismonda 1842 (Syn. an. inv. p. 27.) nomine 
Cyclostomatam , tamquam Gasteropodorum sectionis, Cyclo- 
stoma et Helicinam complectitur. 
CL Jay 1850 (Catal. of Shells p. 251.) familiam Cyclo- 
stomaceoram statuit, cujus genera sunt: Pupina , Trunca- 
tella , Cyclostoma , Geomelania , Helicina , Stoastoma. 
Dividendus videtur ordo Pneumonopomorum ex animalium 
structura externa , nempe positione oculorum , in subordines 
duos: Opisopkthalma (Auriculaceis affinia) et Ectophthalma . 
