USTRATIONS. 



Page. 



Plate I. Diagram illnstratiug geologic distribution of families 134 



Fig. 1. Diaoram giving the geologic distribution of tbe bracbiopod orders ... 96 



2. Stages of growtb of tbe lophopbore in Thecidea, Cistella, and Mega- 



tbyris ; - - - • ^^^ 



3. Stages of growtb of tbe lopbopbore in tbe Terebratellida^ and Tere- 



bratulidiB l*-'9 



4. Metamorphoses of the bracbidium in Dielasma turgida 110 



5. Early stages of tbe lopbopbore of Glottidia and adult bracbia in 



Lingula and Hemithy ris ^^^ 



6. Metamorpboses of tbe bracliidium of Zygosiura and tbe bracbidium 



111 



of Rbyncbospira ^^^ 



7 



