Plate XVI. 



(All the specimens are in the collection of the Museum of Comparative 

 Zoology at Cambridge.) 



Page. 

 Figs. 1-8. RJiopalithcs nocE, showing the varieties produced by greater or 



less acceleration (1109, iioi, 1107, mo, ion, , 1108, 1108).... 139 



(188) 



I 



