GRADATION AMONG ANIMALS. 
SECONDARY. TERTIARY 
PRIMARY. 
RADIATES. MOLLUSKS. ARTICULATES. 
_————— eae 
Polyps. Acalephs. 
Present, «+++++}eseeeee| eee 
——, 
Echino- 
Gastero- Cephalo- 
derms. 
Acephala. pode. poda. 
Son Os it re is er rt 
Pliocene, esse e[eecaccalecccceslescsccssccleccvcve|cece sesleusseseslseccsccs 
Miocene, sees] evecces|sennnae [accscececcl(ecscccslevescctlsusscscslscecces 
Eocene,++eere|sesases| eevee 
Cretaceous,+++|++-ees-|esee 
JULASSIC, ers eee |eeeeees| ence 
Seele cere eseselesecersleeseees|sescesne| seeces 
ees Cs errr rid ry 
Triassic, eevess|occecccleccscesl(ecvecesees|eocccer| scccccslccncenecl|ecccecs 
Permian, «2+ 2c] ecccces| sesccee|sescccccce| sccccce|scccccslsscccccslssccsces 
-—A—_—_—____+,, 
Worms. Crustacea. Insects. Fishes. Reptiles. Birds. Mammalia. 
eee eeseleeseoees 
se eweseleeeeeces 
Ss i id 
Sees eee ey 
CATDONsPETOUNS || (e) ojuro/«||;o\wieve elena) siatarsjeietutere ail fiaiataasm sll eierelertie | ates’ e/aletarol| ‘atatereiefetell asta sMUNTBRG bare ents 
Devonian, +2-|+seeees|eoccccslsecsecsccclerccvvrlscssses|seccseselseceese 
Silurian,...Polyps. Acalephs. 
Azoic. 
Echino- 
Gastero- Cephalo- 
derms. 
Acephala. poda. poda. 
VERTEBRATES. 
~ 
CO ed ts we er srr iy 
Cee die ry 
«+++! True Mammalia. 
ee eeeeleeeeee|«+e-Marsupials...+« 
eee eel eee eBirds.c cess eecseeces 
«+ Reptiles... scecsesseencceees 
Worms. Crustacea,«+++++++-Fishes.ssssseseseesercrssscsseecess 
