Pineal Organs and Adjacent Parts of the Bram in Tuatara. 629 



Thus the mixed culture of Azotobacter and Fscndomonas gave an increase 

 of 35 milligi'ammes of nitrogen on the limed soil, and an increase of 25 milli- 

 grammes of nitrogen on the unlimed soil. 



This gain of nitrogen was not due to any material present in the culture 

 solution, for the autoclaved culture solution shows a gain of 6 milligrammes 

 of nitrogen only, derived chiefly from the dead bacteria in the solution. 



Taking an acre of soil 4 inches deep as weighing about 1,000,000 lbs., a 

 gain of 35 milligrammes of nitrogen per TOO grammes would represent an 

 increase of nearly 350 lbs. of nitrogen per acre. 



That the nitrogen fixed by this mixed culture of bacteria in the soil is 

 readily assimilated by. plants is shown by a number of experiments now in 

 progress, full details of which will be described in a future communication. 



On the Structure, Development, arid Morphological Interpretation 

 of the Pineal Organs and Adjacent Parts of the Brain in the 

 Tuatara (Sphenodon punctatus). 



By Arthur Dexdy, D.Sc, F.R.S., Sec.L.S., Professor of Zoology in King's 

 College (University of London). 



(Received June 22,— Read June 30, 1910.) 



(Abstract.) 



The memoir of which an abstract is here given contains a detailed 

 account of the pineal, organs and associated parts of the brain in 

 Sphenodon, from the morphological, histological, and embryological points of 

 view, accompanied by numerous illustrations, and may be regarded as a 

 continuation and amplification of my earlier work on the subject. 



Tlie material upon which my results are based consisted partly of a number 

 of adult living Tuataras presented to me by the New Zealand Government, 

 the cost of transmission of which to England was defrayed by a grant from 

 the Government Grant Committee, and partly of specimens (chiefly embryos) 

 preserved by myself while in New Zealand. I defer the expression of my 

 thanks to the numerous friends who have helped me in the work until the 

 publication of the complete memoir. 



As I have already pointed out in my work on the intracranial vascular 

 system,* there is in Sphenodon a very extensive subdural cavity between the 

 brain and the cranial wall, and advantage was taken of this fact to fix the 



* 'Phil. Trans.,' B, 1909. 



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