244 ANIMAL PARASITES. 



Second Sub-class. 



Trematoda = Myelmintha (Diesing) = Egelwiirmur Platyelmia 

 isolata = Isolated Flat-worms (Kiichenmeister). 



Animalia solitaria, plerumque hermaphroditica, rarissime sexu 

 distincto et poris plerumque suctoriis, medianis aut lateralibus 

 instruct a. Canalis cib arms fur catim divisus aut ramosus, rarissime 

 simplex. Evolutio fit plerumque metamorphosi et sapissime 

 generatione alternante, rarissime sine illis. (Leuckart, in Van der 

 Hoeven.) 



Although Leuckart does not place the Monostoma as a distinct 

 order beside the Distoma, but as a subdivision of the latter, 

 I still allow them to stand here as a distinct family, as this is the 

 general practice, and no important error can result from the 

 retention of this division. Any one who does not agree with 

 this has only to place the section upon Monostoma after that 

 which treats of the Distoma. 



Familia I. Monostoma = Tribus II. Monocotylea ; 

 XVIII. Monostomum (Diesing). 



Synon. Cucullanus ; Festucaria ; Fasciola ; Amphistoma ; 

 Distoma et Monostoma. 



" Corpus depressum vel teretiusculum ; caput continuum vel collo 

 discretum. Os terminate vel anticum } ut plurimum acetabuliforme, 

 integrum, crenulatum, inerme v. armatum. Apertura genitalium 

 perclara, duplex ; mascula infra os } interdum, acetabuliformis } pene 

 protractili ; feminea pone masculum, minima, ut plurimum incon- 

 spicua. Porus excretorius supra caudae apicem anteri margine 

 caudali. Animalia mammalium, avium, amphibiorum et piscium 

 corpora, i. e., prater tractum intestinalem organa varia inhabitantia, 

 libere aut folliculis inclusa." (Diesing.) Metamorphosis et 

 generatio alternans inter evolutionem, uti in Distomis. The ventral 



