ILL US TRA TIONS xxiii 



FIGURE PAGE 



121. Stages of growth of the lophophore in Thecidea, Cistella, and 



Megathyris 279 



122. Stages of growth of the lophophore in the Terebratellidse and 



Terebratulidae 280 



123. Metamorphoses of the brachidium in Dielasma turgidum . . . 281 



124. Early stages of lophophore of Glottidia and adult brachia in 



Lingula and Hemithyris 282 



125. Metamorphoses of brachidium of Zygospira and adult brachid- 



ium of Rhynchospira 284 



126-128. Development of internal apparatus in Homceospira evax . 365 



129. Deltidial development in Spirifer 384 



130. Deltidial development in 1, 2, Spiriferina pinguis Deslong- 



champs ; 3, 4, Spiriferina Walcotti Sowerby; 5, Spiriferina 



rostrata Schlotheim 393 



131. BiloUtes varicus Conrad ; ventral area 402 



132. Genesis of Bilobites ... 404 



