194 PUPILLIDAE AND RELATED GROUPS, 



pecially its internal teeth. In shell form and in peristome, 

 the sg. Discostrohilops approaches Vallonia; the principal 

 anatomical distinction of StroMlops is the apical prolongation 

 of its penis which somewhat resembles either of the two 

 "diverticula" of Acanthinula. In addition, its radular cen- 

 tral is about as wide as its first lateral. 



Strobilops aenea Pilsbry. Plate 26, figs. 5 to 8. 



The animals studied were collected during May, 1928, in 

 Springfield Township, near Philadelphia, Pa. ; in most of the 

 individuals of this lot and in all those from Necaxa, Mexico, 

 the vas deferens ends near the base of the spermatheca and 

 the other male organs are lacking. Embryos have not been 

 observed. 



Mantle edge (fig. 8) broad; lappets weak; glands encroach- 

 ing on lung. Lung more than 3 times its base or 4 times 

 length of kidney. Principal vein very close to kidney ; weak 

 venation present along columellar side and anteriad. Kidney 

 (broader, longitudinally trabeculate region) about as long as 

 its base or length of pericardium ; orthureter about 3 times 

 as long, similarly thick- walled but with weak transverse trabe- 

 culae ; recurved groove short. 



Ovotestis (fig. 7) imbedded in basal end of apical liver lobe; 

 consisting of two lobes, each divided into few, short-clavate 

 lobules; duct thickened below middle in animals with male 

 organs; carrefour clavate with ovoid base; talon not devel- 

 oped. Spermatheca clavate, short-stalked and imbedded in 

 side of oviduct. Vagina very long. Prostate short with 

 clavate alveoli. Epiphallus (fig. 5) developed in vas deferens, 

 some distance above entrance into penial side through a low 

 papilla. Penis bifurcate; appendicular arm clavate and 

 shorter than epiphallar, which extends beyond entrance of vas 

 deferens; appendix elongate fusiform and thin- walled, enter- 

 ing apex of appendicular penial arm through a thickened 

 ring. Penial retractor arising from diaphragm, bifurcating 

 below its middle and inserting near apex of appendicular arm 

 and alongside entrance of vas deferens on epiphallar branch. 

 Atrium short, opening near right inferior tentacle. 



