413 



Number of Species* of Small Botto.m Am.m.^ls i.\ 1923 Collections Compabed 



WITH Ni-MiiEB Missing in S.vme CoLLraxio.Ns o.x Basis of 1913-1915 Recobds 



Alt. Zones Co-Miilnkii 



* Includes no mus.sels except a very few young individuals or dwarf species 

 such as are occasionally taken with small apparatus. 



t Pollutional or tolerant, t Cleaner preference spp. ^ Xow missing. 



