38 Bevieics — Prof. A. Gaudry — On Evolution. 



so that we must say that this form was coniined to these older 

 formations. The Eugosa have had their extension in Primary times. 

 It is very likely that many roots have been the parent-stock of the 

 Corals of the Secondary period ; since they pass insensibly into 

 these ; but without doubt all of them have not been their ancestors. 

 Some among the Tabulata of ancient formations such as HelioUtes 

 seem to have been the ancestors of the recent Alcyonarians : on the 

 other hand, Michelinia, Halysites, and many others have been entirely 

 confined to the Primary formations. Angelin's work on the Crinoids 

 admirably shows the diversity of these animals in the Silurian epoch; 

 surely such an abundance and variety of forms was not necessary 

 for culminating in the present species whose existence the latest 

 dredgings have revealed. The same must be said of the Primary 

 Brachiopoda ; certain of these have been continued changed or un- 

 changed to our own times, but the immense majority of the genera 

 of Orthises, Produdi, and Spirifers has had no influence on the 

 Brachiopoda of our seas. The Primary Pteropods and Nucleo- 

 branchiates may have been the ancestors of those which followed 

 them ; nevertheless they have been so changed, that there is no risk 

 of confounding the ancient genera with the newer. With the ex- 

 ception of Nautilus, no form of the family Nautilidcs, which in former 

 times had such extreme fecundity, is represented in our day. The 

 Trilobites, the variations of which have shown such an astonishing 

 plasticity in Cambrian and Silurian times, diminished during , the 

 Carboniferous period, and their last species has been found in the 

 Permian.^ 



" The Merostomata are at the present day only represented by the 

 genus Limulus. It is not for producing this isolated survivor of so 

 many singular creatures that the groups Xyphosurid^ and Eury- 

 pterid^ were developed so largely in Palaeozoic times. 



" I believe that many of the ancient Fishes have been the prototypes 

 of the present ones ; but some amongst them, such as Pterichthjs, 

 Cephalaspis, Coccosteiis, constitute a strange population confined to 

 primary times ; and Labyrinthodont reptiles characterized the end 

 of the Primary and the beginning of the Secondary period. Those 

 fossils which have been specially characteristic of certain periods in 

 the history of our earth, render invaluable assistance to the geologist 

 in the determination of the strata ; they well deserve the name of 

 " Medals of Creation " which Mantell gave them, for they indicate 

 exactly geological epochs. 



"Inequality in Evolution. — It arises from what has just been said 

 that there have been great inequalities in the development of beings 

 in ancient times. These inequalities do not confirm the idea of a 

 struggle for life in which victory would be to the most highly gifted. 

 Paleontology shows us that the contrary maj'^ have been the case. 



" Many organisms may have been like transitory dynasties, they 

 have become salient individualities, which have given to their epoch 

 a marked physiognomy ; even as we speak of the age of Charle- 



1 This supposed Permian Trilobite is erroneous. No Trilobite occurs higher in 

 the series than the Carbonil'erous formation.— Edit. Geol. Mag. 



