114 Messrs. Evans and Smith on the Magnetic [Mar. 16, 



pendix " is given ; and here the author takes occasion to describe much 

 earlier stages of the skull in typical birds, viz. in the Crows. The primordial 

 parts of the facial arches are carefully compared, beginning at the lowest 

 Fishes, and ascending to the Mammalia ; the pattern and habit of growth 

 of the facial structures in the higher classes is shown to be adumbrated 

 by the condition of these parts in the Lamprey (Petromuzori). The 

 essential independence of the two arches in front of the mouth is as- 

 serted, and their low type of development is shown in the non-segmentation 

 of the parts that should answer to the free postf-stomal rays, the mandible, 

 and the hyoid arch. 



A survey is also made of the system of secondary bones bones which 

 have no preexistent hyaline cartilage as their basis ; and these are shown 

 to pass insensibly into dermal plates : the only distinction that can be 

 made, viz. into dermal, subcutaneous, and aponeurotic bones, is there 

 explained to be merely useful, but not to have anything embryologically 

 essential in it. 



March 16, 1865. 

 Major-General SABINE, President, in the Chair. 



Pursuant to notice given at the last Meeting, Dr. Watson proposed, and 

 Dr. Sharpey seconded, the Right Honourable Lord Justice Turner for 

 election and immediate ballot. 



The ballot having been taken, Lord Justice Turner was declared duly 

 elected a Fellow of the Society. 



The following communication was read : 



"On the Magnetic Character of the Armour-Plated Ships of the 

 Royal Navy, and on the effect on the Compass of particular 

 arrangements of Iron in a Ship." By FREDERICK JOHN EVANS, 

 Staff-Commander R.N., F.R.S., Superintendent of the Compass 

 Department H.M. Navy, and ARCHIBALD SMITH, M.A., F.E.S., 

 Corresponding Member of the Scientific Committee of the Im- 

 perial Russian Navy. Received March 9, 1865. 



(Abstract.) 



This paper contains a reduction and discussion of all the observations of 

 deviation and of horizontal and vertical force made in the armour-plated 

 ships of the Royal Navy, and also in certain iron-built ships of the Royal 

 Navy and of the mercantile marine. It may be considered as a continua- 

 tion of a paper on the Deviation of the Compass in iron-built ships of the 

 Royal Navy, by Staff Commander Evans, published in the Phil. Trans, 

 for 1860, p. 337. 



The reduction gives the numerical values of the several parts of the 



