4<18 THE NATUEAL HISTORY EETIEW. 



There is, however, great variation in the position of the brain with 

 regard to the beak in different families of birds ; the base of the brain 

 being in some cases nearly at right angles to the opening of tbe 

 bill, and in others inclined at but a slight angle to it. This more or 

 less vertical position of the brain appears to be dependent on the 

 greater or less development of the orbits of the eyes. In the Wood- 

 cock, for instance, where the eyes are very large in proportion to the 

 brain, the base of the latter is nearly vertical to the opening of the 

 beak, and when the skull of such a bird, even with both mandibles 

 removed, rests with its under side upon a horizontal surface, the 

 position of the base of the brain is nearly vertical. From the position 

 of the skull of the Archseopteryx upon the slab it would appear to 

 have been detached from the neck before being finally embedded in 

 the mud from which the Solenhofen limestone was formed. There 

 is, as will subsequently be seen, some reason also for supposing that 

 the maDdibles had become detached ; but at all events the skull 

 appears to have lain upon the shore, with the base downwards, as 

 probably presenting the best surface on which to rest, and with the 

 frontal region upwards. But the base of the cast of the brain ap- 

 pears to be nearly vertical to the slab, which is split so as to display 

 the old shore surface. It seems, therefore, probable that the base of 

 the brain may in the Archseopteryx have formed nearly a right angle 

 with the opening of its beak, and if so, that as is the case with most 

 other birds with the same peculiarity, its eyes were of large size, and 

 the brain placed quite at the back of the head. But enough has 

 been said of a hypothesis built upon such slender foundations, and 

 I will therefore now describe another object upon the same slab, 

 some of the details of which appear to have escaped the attention 

 of previous observers. 



On the principal slab in the angLj between the right femur and 

 tibia is a small V shaped object, the longer of the two limbs about 

 li inches in length, made up partly of mineralized bone and partly 

 of impressions of other portions of the same bones preserved in the 

 counterpart slab. Prom its form it had, I believe, been considered as 

 possibly representing the beak of the Archseopteryx ; but great was 

 my surprise when I detected along its right hand margin, towards 

 the apex, the distinct impression in the slab of four teeth still 

 attached to it. The teeth themselves remain engaged in the counter- 

 part, and are easily recognized by the lustre of their enamel. There 

 seems also to be a portion of a fifth tooth visible, which has been 

 displaced and lies across the base of that nearest the point of the 



