404 



FOSSILS OF THE 



[Ch. XXV. 



It will be seen that the more ancient corals have what is called a 

 quadripartite arrangement of the stony plates or lamellae^ — parts of the 

 skeleton which support the organs of reproduction. The number of 

 these lamellse in the paleozoic type is 4, 8, 16, &c. ; while in the newer 

 type the number is always 6, 12, 24, or some other multiple of six ; and 

 this holds good, whether they be simple cup-like forms, as in figs. 514 a 

 and 515 a, or aggregate clusters of cups as in 514 c. 



It is not enough, therefore, to say tliat the primary or more ancient 

 corals are all generically and specifically dissimilar from the secondary, 

 tertiary, and living corals, — for, more than this, they belong to distinct 

 Orders, although often so like in outward form as to have been referred 

 in many cases to living reef-building genera. Hence v/e must not too 

 confidently draw conclusions from the modern to the paleozoic polyps, 

 respecting climate and the temperature of the waters of the primeval 

 seas, inasmuch as the two groups of zoophytes are constructed on essen- 

 tially different types. When the great number of the paleozoic and neo- 

 zoic species is taken into account, it is truly wonderful to find how con- 

 stant the rule above explained holds good ; only one exception having as 

 yet occurred of a quadripartite coral in a neozoic formation (the creta- 

 ceous), and one only of the sextuple class (a Fungia ?) in paleozoic 

 (Silurian) rocks. 



From a great number of lamelliferous corals met with in the Mountain 

 Limestone, two species have been selected, as having a very wide range, 

 extending from the eastern borders of Russia to the British Isles, and 

 being found almost everywhere in each country. 



Fig. 516. 



Pig. 51T. 



Lithostrotion 'baHoltiforme, Phil. sp. {Li- 

 thostrotion stfiatum, Fleming; Astrcea 

 lasalti/ormis, Conyb. and Phill.) Ken- 

 dal ; Ireland ; Eussia ; Iowa, and west- 

 ward of the Mississippi, United States. 

 (D. D. Owen.) 



Lonsdateia floHformis (Martin, sp.) 

 M. Edwards. {^LithoHtrotionfioriforme^ 

 Fleming. Strombodes.) 



a. Young specimen, witli buds on the 

 disk. 



&. Part of a full-grown compound mass. 

 Bristol, &c. : Eussia. 



These fossils, together with numerous species of Zaphrentis^ Amplexus^ 

 Cyathophyllum, CUsiophyllum^ Syringopora, and Michelinea,^' form a 

 group widely different from any that preceded or followed them. 



* For figures of these corals, see Paleontographical Society's Monographs, 1852. 



