MUSEUM OF COMPARATIVE ZOOLOGY. 165 



EXPLANATION OF THE PLATKS. 



The figures of shells wore drawn by Mr. Arthur F. Gray ; those ut' geuiulia and lingual dentition, 



by W. G. Biuuey. 



PLATE I. 



Fig. A. Mesodon Chiloweensis : lingual dentition. 

 " B. " genitulia. 



' C. Patula Bryanti. 



" D. Helicodiscus fimbriatus. 



" E. Triodopsis Levettei. 



" F. Zonitcs petrophilus. 

 " G. " Whcatleyi. 



II. Vitrinozonites latissimus : lingual dentition. 



" I. Arionta intercisa : lingual dentition. 



" J. Triodopsis Copei. 



" K. Arionta Mormonum, var. circuincarinata. 



" L. Zonites Upsoni. 



PLATE II. 



Fig. A. Zonites placentula. 

 " B. " inaeilentus. 

 " C. " cuspidatus. 

 " I). Andrews!. 



" E. Lawi. 



" F. " nuiltidentatus. 

 " G. significans. 



" II. Kugeli : shell. 



' I. dentition. 



" J- subplanus : dentition. 



" K. Mesodon Chiloweensis. 

 " L. Andrews!. 



" M. Macrocyclis Henijiliilli. 



" N. Microphysa Stearnsi : dentition. 

 " 0. jaw. 



