XXX11 



FACTS AND OBSERVATIONS. 



TABLE Q. Bohemian Life as exhibited in Fauna E. e. 2. 



Orders &c. 



Species. 

 Total. 



Genera, with their Species. 



Plantee none. 



Amorphozoa 5 Ischadites, 1 ; Stromatopora, 4. 



Coelenterata 12 Cystiphyllum, 2 ; Favosites, 3; Halysites, 1 ; Heliolithus, 5 ; Omphyma, 1. 



Cystidea 1 Scyphocrinites, 1. 



Annelida 1 Cornulites, 1. 



Cirripedes none. 



Trilobita 76 Acidaspis, 20 ; Arethusina, 1 ; Calymene, 4 ; Cheirurus, 7 ; Bronteus, 7 ; Cromus, 2 ; 



Deiphon, 1 ; Cyphaspis, 5 ; Harpes, 5 ; Illasnus, 2 ; Phacops, 6 ; Proetus, 7 ; 



Lichas, 5 ; Spharexochus, 2 ; Staurocephalus, 1 ; Trilobita, 1 . 

 Entomostraca ... 4 Ceratiocaris, 2; Eurypterus, 1 ; Leperditia, 1. 



Polyzoa 5 Dictyonema, 2; Fenestella, 1 ; Eetepora, 1 ; Retiolites, 1. 



Brachiopoda 46 Atrypa, 11 ; Chonetes, 3; Discina, 1 ; Lingula, 1 ; Orthis, 4; Pentamerus, 3; Po- 



rambonites, 1 ; Mimulus, 2 ; Retzia, 1 ; Rhynchonella, 2 ; Spirifer, 1 1 ; Stro- 



phomena, 5 ; Trematis, 1. 



Monomyaria 7 Avicula, 7. 



Dimyaria 36 Antipleura, 2 ; Astarte, 1 ; Cardiomorpha, 1 ; Cardiola, 4; Cardium, 4 ; Cypricar- 



dium, 3 ; Hemicardium, 3 ; Isocardia, 3 ; Lucina, 3 ; Lunulacardiuni, 3 ; My- 



tilus, 4 ; Pholadomya, 2 ; Silurina, 3. 

 Pteropoda 13 Conularia, 1 ; Cyrtolites (Bellerophon), 8 ; Ecculiomphalus, 2 ; Phragmotheca, 1 ; 



Pterotheca, 1. 

 Gasteropoda 125 Acroculia, 29 ; Calyptraea, 1 ; Cirrus, 6; Delpbinula, 3 ; Euomphalus, 18 ; Gyro- 



trema, 2 ; Loxonema, 4 ; Murchisonia, 8 ; Natica, 4 ; Naticella, 4 ; Patella, 1 ; 



Pilidion, 1 ; Porcellia, 3 ; Pleurotomaria, 9 ; Rotella, 2 ; Subulites, 1 ; Trochus, 



9 ; Tubina, 4 ; Turbo, 12 ; Turritella, 4. 

 Cephalopoda 590 Ascoceras, 10 ; Aphragmites, 2 ; Glossoceras, 2 ; Cyrtoceras, 199 ; Gomphoceras, 59 ; 



Nautilus, 5 ; Orthoceras, 252 ; Phragmoceras, 25 ; Trochoceras, 36. 

 Class uncertain ... 1 Lobolithus, 1. 



Total . 922 



This Table contains 94 genera and 922 species. 



It is difficult to discover any mutual dependence among the numbers of this community as at 

 present open to our examination. 



The carnivorous animals could not have subsisted on what we now see, unless they fed on each 

 other ; for they greatly outnumber the herbivorous or infusorial feeders, contrary to the usual pro- 

 portions. I have twice found Bellerophons in the chambers of Orthocera ; M. Barrande has found 

 young Orthocerata there. The simpler organisms are in this bed exceedingly few. 



The Brachiopoda are in patches, the genera very poor in species, except Atrypa and Spirifer. 

 M. Barrande expressly states that there is not the vestige of a plant in all the beds (Defense des 

 Colonies, 1865, p. 304). 



Compensation must have been found in animals of a soft structure, which of course have left 

 no traces. 



The five orders Trilobita (sixteen genera), Dimyaria (thirteen genera), Brachiopoda (thirteen 

 genera), Gasteropoda (twenty genera) , and Cephalopoda (nine genera) exhibit remarkable variety in 

 their forms of life, and the last two are wonderfully abundant ; and we miss among others the large 

 order Echinodermata. If we look at the species in this subdivision, we find the genera Calymene 

 and Phacops but poor, and the others, except Acidaspis, very poor. Orthis, Rhynchonella, Penta- 

 merus, and some more Brachiopodal genera are slenderly represented. 



M. Barrande's new genera Mimulus, Antipleura, Gyrotrema, and Silurina are here. 



It is evident from the argillaceo-calcareous nature of the sediment, from the predominance of 

 free-swimmers, and from the absence of vegetation and of the Annelida, that the Silurian sea was 

 then deep, but not too much so for the coexistence of numerous Dimyaria and Gasteropoda. 



Although the mineral passage from any one of M. Barrande's subdivisions into the next is 

 always insensible, or at least slow, the species belonging to bed E. e. 2 very rarely ascend into 

 i*-et~3-er*4, while it is very common for a species first appearing in E. e. 1 to find its way into 

 E. e. 2, and then to disappear for ever. 



