374 Mr Shipley, On the Nervous System. [Mar. 1, 



the integrals 



rx 



iz x = (— A; 2 sn 2 #) dx, 

 Jo 

 rx 

 gzx = I k 2 crfxdx, 

 Jo 

 rx 

 ezx= dn 2 xdx ; 

 Jo 



of these the functions depending upon gz x are more regular and 

 symmetrical than those depending upon iz x and ez x. The two 

 periods of the doubly-periodic functions sngx, cngx, dngx are 

 4£ and UG' (where G = E- k' 2 K, G' = E' - k 2 K'), corresponding 

 exactly to 4tK and 4>iK' in the case of the elliptic functions. 



(3) On the movement of solids through ether. By Mr A. H. 

 Leahy. 



(4) On Mr Gallons anthropometric apparatus at present in 

 use in the Philosophical Library. By H. Daewin, M.A., and R. 

 Theelfall, B.A. 



The authors exhibited and described some of the apparatus 

 used by Mr Galton for his anthropometric measurements, and then 

 gave an account of improvements and modifications which they 

 had suggested in some of the instruments. 



March 1, 1886. 



Peof. Fostee, Peesident, in the Chaie. 



The President explained that the meeting on February 15 had 

 not been held in consequence of the funeral of Mr Bradshaw, and 

 referred to the loss the University had sustained by his death. 



The following communications were made to the Society : 



(1) On the Development of the Nervous System in Petromyzon 

 fluviatilis. By A. E. Shipley. 



The author commenced his communication by describing the 

 formation of the neural cord from a solid keel of epiblast. He 

 pointed out that the central canal arose by the separation of the 

 cells in the middle line, and that the canal is not lined by cells 

 involuted from the epidermic epiblast, as previous observers have 

 stated. The formation of the primary vesicles of the brain was 

 then described ; and the origin of the 2nd, 5th, 7th, 9th and 10th 



