M. Miiller on the Development of the Lycopodiaceae. 27 



actually then occupied by the clear unossified cartilaginous basis 

 of the bone, and not by marrow. The non-medullary character, 

 therefore, assigned to fishes from the texture of their bones is 

 strictly accurate. They may have cavities, but these are never 

 occupied, as in higher classes, by marrow. The persistent carti- 

 laginous basis of such partially ossified bones of fishes differs in 

 chemical composition from the temporary cartilage of the bones 

 of reptiles, birds and mammals, as Prof. Miiller has shown*. 

 It bears a closer resemblance to mucus : it requires a thousand 

 times its weight of boiling water for its solution, and is neither 

 precipitated by infusion of galls, nor yields any gelatine upon 

 evaporation. 



I have been induced to offer the foregoing comments on Mr. 

 Tennant^s Ichthyolite from having been asked more than once 

 to explain the seeming contradiction given by such fossils to the 

 law of the absence of medullary cavities in the bones of fishes, 

 and from the circumstance of there being no precise explanation 

 of the appearance, in reference to the cavities in the bones of 

 higher Vertebrata, in the classical work of M. Agassiz on fossil 

 fishes. 



V. — On the Development of the Lycopodiacese. 

 By Karl MuLLERf. 



[With five Plates.] 



§ 1. Literature. 



The most complete researches on this interesting family which 

 have hitherto been presented to us are certainly those of Bischoff, 

 which he published in his ^ Cryptogamische GewachseJ.' Since 

 that time however the position of science has undergone such an 

 important change, that in this family also questions have arisen 

 which remain to be solved. Toward the attainment of this end 

 the present memoir is contributed. I know well that there is 

 yet many a gap to be filled up here, still I am induced to publish 

 my observations in their present condition, as I believe them to 

 be conclusive in reference to many points. 



The history of this family up to the time of Bischoff has been 

 given by him in his above-mentioned work. This relieves me 

 from the necessity of entering upon it here. What has been 

 done since, is chiefly confined to their systematic arrangement, 



* See his admirable memoir, * Ueber die Myxinoiden,' in the Berlin 

 Transactions for 1835. 



t From the ' Botcinisdie Zeitung,' July 31, and August 7, 1816. Trans- 

 lated by Arthur Henfrey, F.L.S. &c. 



t 2te Liefcrung, Nuremberg, 1828. 



