34 



BULLETIN 720, U. S. DEPARTMENr OF AGRICULTURE. 



Table II. — Items of animal food identified in stomachs of mallard ducks and the number 

 in which found— Continued. 



Kind of food. 



Total number of .stomach.s examined. 



Class Gastropoda (Univalves)— Continued. 

 Triforidse. 



Triforis sp 



Cyliehnidse. 



Cylichna canaliculata 



Zonitidse. 



Vitrea sp 



Helicidse. 



Polygyra espiloca 



Polygyra sp 



Pupidse. 



Vertigo sp 



Succineidae. 



Succinea avara 



Aiiriculidse. 



Melampus bidentatus 



Lymnseidse. 



Lymnxa columella .- 



Lymnsea palustris '. 



Lymnsea techella 



Lymnxa truncatua 



Lymnxa sp 



Planorbis alabamensis 



Planorbis campanulatus 



Planorbis dilatatus 



Planorbis duryi 



Planorbis exacuous 



Planorbis Mrsutus • 



Planorbis opercularis 



Planorbis parvus 



Planorbis trivolvis 



Planorbis vermicnlaris 



Planorbis wheatleyi 



Planorbis sp 



Pompholyx costata 



Segmentina armigera 



Segmentina obstricta 



PhysidfE. 



Physa ancillaria 



Physa heterostropha 



Physa sp 



Class Pelecypoda (Bivalves). 



Unidentified 



Myidse. 



Mya arenaria (soft-shell clam) 



Mactridse. 



Mulinia lateralis 



Rangia cuneata 



Telltnidae. 



Macomiafusca., 



Common 

 mallard. 



1,72.5 



Black 

 duck. 



