a 
MUSEUM OF COMPARATIVE ZOOLOGY. 165 
EXPLANATION OF THE PLATES. 
The figures of shells were drawn by Mr. Arthur F. Gray ; those of genitalia and lingual dentition, 
by W. G. Binney. 
GACH 1 
. Mesodon Chiloweensis : lingual dentition. 
s f genitalia. 
Patula Bryanti. 
Helicodiscus fimbriatus. 
Triodopsis Levettei. 
Zonites petrophilus. 
«  Wheatleyi. 
Vitrinozonites latissimus : lingual dentition. 
Avrionta intercisa: lingual dentition. 
Triodopsis Copei. 
Arionta Mormonum, var. circumcarinata. 
Zonites Upsoni. 
HASH Os DOW > 
PLATE IL. 
Zonites placentula. 
macilentus. 
««  euspidatus. 
cs Andrewsi. 
Lawi. 
*«  multidentatus. 
significans. 
Rugeli: shell. 
s . dentition. 
subplanus: dentition. 
Mesodon Chiloweensis. 
es Andrewsi. 
. Macroecyclis Hemphilli. 
Microphysa Stearnsi: dentition. 
“ jaw. 
“ce 
OM EP AUN MORSE Ob > 
