XIII. On the structure and development of the skull in the pig ( Sus scrofa )

I have for some years past determined to concentrate my attention on some one type of Mammalian Skull, so as to be able to present to the Royal Society a paper similar to those which have already appeared other Vertebrate Skulls. I was led to work out this medium type, and not a more generalized form, such as the Guineapig (see “On the Development of the Frog’s Skull,” Phil. Trans. 1871, p. 203), through the circumstance of an offer from my friend Mr. Charles Stewart to put some seventy embryos the Common Pig into my possession. In the present communication I have had the invaluable help of advice and oversight from Professor Huxley, whilst the labour of my hands has been lightened by my son, T. J. Parker, who prepared for me all the more delicate sections.