CHAPTER XII 

 1859-1860 



The programme laid down in 1857 was steadily carried 

 out through a great part of 1859. Huxley published nine 

 monographs, chiefly on fossil Reptilia, in the proceedings 

 of the Geological Society and of the Geological Survey, 

 one on the armour of crocodiles at the Linnean, and " Ob- 

 servations on the Development of some Parts of the Skele- 

 ton of Fishes," in the Journal of Microscopical Science. 



Among the former was a paper on Stagonolepis, a 

 creature from the Elgin beds, which had previously been 

 ranked among the fishes. From some new remains, which 

 he worked out of the stone with his own hands, Huxley 

 made out that this was a reptile closely allied to the Croco- 

 diles ; and from this and the affinities of another fossil, 

 Hyperodapedon, from neighbouring beds, determined the 

 geological age to which the Elgin beds belonged A good 

 deal turned upon the nature of the scales from the back and 

 belly of this animal, and a careful comparison with the 

 scales of modern crocodiles — a subject till then little inves- 

 tigated — led to the paper at the Linnean already men- 

 tioned. 



The paper on fish-development was mainly based upon 

 dissections of the young of the stickleback. Fishes had 

 been divided into two classes according as their tails are 

 developed evenly on either side of the line of the spine, 

 which was supposed to continue straight through the centre 

 of the tail, or lopsided, with one tail fin larger than the 

 other. This investigation showed that the apparently even 

 development was only an extreme case of lopsidedness, the 

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