1903.] NATURAL SCIENCES OF PHILADELPHIA. 629 



is evidently a herbivorous slug. The crop and stomach of the speci- 

 men dissected were filled with the curiously marked leaves of Frullania 

 ( Jungermanniacese) . 



Explanation of Plate XXVIII. 



Fig. 1. — Central nervous system of Zacoleus idahoensis. 



Figs. 2, 3. — Jaws. 



Fig. 4. — Intestine. 



Fig. 5. — Genitalia: o, common external orifice; ov., oviduct; j)., penis; sip. 



spermatheca; sip.d., duct of the spermatheca. 

 Fig. 6. — Free retractor muscles. 

 Figs. 7-11.— Teeth. 



