165 



Crenilabrus comubicus, Yarr. 

 36 Leuciscus rutilus, Yarr. 



Leuciscus dobula, Yarr. 



Leuciscus ]jhoxinus, Yarr. 



Cobitis barbatula, Yarr. 



Salmo salar, Yarr, 

 40 Salmo caecifer, Pamell. 



Osmerus eperlanus, Yarr. 



Coregonus inarsnula, Yarr. 



Alosa finta, Yarr. 



Gadtis morrhua, Yarr. 

 46 Gadus aeglefinus, Yarr. 



Merlarigus vulgaris, Yair. 



Merlangus pollachius, Yarr. 



Merlangus carbon arius, Yarr. 



Merlucius vulgaris, Yarr. 

 50 Lota molva, Yarr. 



Motella quiiiquecirrata, Yarr. 



Motella glauca, (in spt.) Yarr. 



llaniceps trifurcatus, Pamell, Zool. 

 Bot. Mag. Vol. I. 



Platessa limanda, Yarr. 

 65 Hippoglossus vulgaris, Yarr. 



Rhombus maximus, Yarr. 



Rhombus vulgaris, Yarr. 



Rhombus birlus, Yarr. 



Rhombus megastoma, Yarr. 

 60 Rhombus amoglossus, Yarr. 



Solea pegusa, Yarr. 



Monochirus lingula, Yarr. 



Moiiochirus minutus, Pamtll. 



Cyclopterus lumpus, Y^arr. 

 66 Echeneis ramosa, Yarr. 



Anguilla acutirostris, Yarr. 



Ammodytes tobianus, Yarr. 



Ammodytes lancea, Yarr. 



Syngnathus typhle, Yarr. 

 70 Scyllius canicula, Yarr. 



Scy Ilium catulus, Yarr. 



Mustelus Isevis, Yarr. 



Spinax acanthus, Yarr. 



Squatina angelus, Yarr. 

 75 Raia batis, Yarr. 



Raia intermedia, Pamell. 



Raia clavata, Yarr. 



Petromyzon marinus, Yarr. 



■ The following communications were read : 



] . On the Constitution of the Earth's Atmosphere in Remote 

 Geological Epochs. By Professor Johnston, Durham. 



This is the first paper of a promised series on the subject here 

 announced. In the present paper the author endeavours to shew, 

 that in remote epochs the atmospliere was more extensive and heav- 

 ier than it is now, that it contained a greater absolute quantity of 

 oxygen, and that this quantity has gradually diminished up to our 

 own era, and is probably still undergoing a sensible diminution. 

 His views are founded partly on speculative considerations, of 

 which it is not possible to give a sufficiently circumstantial abridg- 

 ment, and partly on the evidence of various operations going on at 

 or near the surface of the earth, the tendency of which must, on the 

 whole, apparently be to diminish the quantity and proportion of 

 the oxygen in the atmosphere. In addition to the ordinary and 

 well known causes of deterioration, the author points out a new 

 source of diminution to which his attention has been lately drawn. 

 From experiments made upon the aeriform fluid discharged from 



