PROOFS, ILLUSTRATIONS, AUTHORITIES, ETC. xiii 



the Permian and chiefly to the mountain limestone. A few speci- 

 mens in the Permian. 



" The presence of so few species in the earlier formations tends to 

 strengthen the remark made by M. D'Orbigny, that the Foramini- 

 fera appear to have been subject to a somewhat regular progression 

 both in character and number, the simple forms occurring in the 

 early formations, and that but rarely, and the most complicated not 

 until the cretaceous, tertiary, and recent epochs, and then with pro- 

 fusion."- King's Monograph of Permian Fossils, Palceontogra- 

 phical Society. 



Echinodermata. "The relations of the living and fossil types of 

 the class of Echinoderrns now appear in the most evident manner. 

 The Crinoidea are the prototype of the whole class. Not only does 

 geology show this, but also what we know of the first states of some 

 species of this family equally confirms it. We may even say that 

 the Crinoidea present us with a kind of synthesis of all the families 

 of this class, by the different forms they assume ; for example, in the 

 Cystidea which remind us of the Echinida3, or in the Melocrines, 

 which make a near approach to the Asteriae. It is onl} r the Holo- 

 tlmrise which seem to be exclusively confined to the present creation, 

 and this family is precisely that which occupies the highest rank 

 among the Echinoderrns; while the Crinoidea, which occur at the 

 lower part of this series, would appear to be the first ; then come the 

 Asterise, already numerous in the triassic formations : and finally, 

 the Echinidse, whose greater development characterises the Jurassic, 

 cretaceous, and tertiary formations." Agassiz : Mon6c/raphie des 

 Poissons Fossiles. 



" The Crinoidea of the Palaeozoic period, though very numerous, 

 exhibit but little variety of type ; and in the complete enclosure of 

 the body by polygonal plates, they present a closer approximation to 

 the Cystidea than do the Crinoidea of the secondary period, in which 

 the variety of forms is much greater." Carpenter s Gen. Phys. 

 345. 



Crustacea. " The Trilobites, which are unquestionably the most 

 ancient type of the class Crustacea .... do not go beyond the 

 coal formation, when they are replaced by gigantic Entomostraca, 



which are in some degree the precursors of the Macruri The 



Macruri prevail from the Triassic epoch to the present creation ; 



while the Brachyura are essentially Tertiary It follows from 



this hasty glance that the types whose affinities have been best 

 studied, such as the Trilobites, Macruri, and Brachyura, succeed each 

 other in the series of formations in the order of their organic grada- 

 tion." Agassiz : Monographic des Poissons Fossiles. 



Cirrhopoda. According to the development hypothesis, the Cir- 

 rhopoda should be placed in the upper department of the Crustacea. 

 The young go through a distinct metamorphosis, having, after their 

 liberation from the egg, a form resembling that of the Entomostraca. 

 " Four stages have been described by Burineister as being presented 



