. The dinosaur book : the ruling reptiles and their relatives. Dinosaurs; Reptiles, Fossil. Pituitary The great size of dinosaurs may have been caused by enlargement of the pitui- tary gland. This illustration shows the relatively large size of the pituitary body in relation to the primitive brain of a troodont dinosaur Drawing by John C. Germanii phant's body has been accompanied bv a certain degree of giantism in the brain, but in the dinosaurs not only was the relative size of the brain small, its actual size was also very small. Thus in Stegosaurus, an animal as heavy as a modern elephant,
. The dinosaur book : the ruling reptiles and their relatives. Dinosaurs; Reptiles, Fossil. Pituitary The great size of dinosaurs may have been caused by enlargement of the pitui- tary gland. This illustration shows the relatively large size of the pituitary body in relation to the primitive brain of a troodont dinosaur Drawing by John C. Germanii phant's body has been accompanied bv a certain degree of giantism in the brain, but in the dinosaurs not only was the relative size of the brain small, its actual size was also very small. Thus in Stegosaurus, an animal as heavy as a modern elephant, the brain was no larger than that of a small kitten. Indeed the diameter of the brain in the large dinosaurs was in many cases less than that of the spinal cord, while in size it was much smaller than the brachial and sacral enlargements of the cord in the shoulders and hips which served to control the move- ments of the legs and tail. For instance, in Stegosaurus, as already mentioned, the sacral enlargement was 20 times as large as the brain. As a matter of fact, the dino- saur brain was probably, in the main, a receptor mechanism—a center where the visual images, the odors, and the sounds coming in from the outside world were received so that the animal's activity might be correlated with the environmental con- ditions indicated by these outside stimuli. One interesting development in the dino- saurs was the great enlargement of the pituitary body attached to the base of the brain. In all but the "giants" among recent vertebrates this pituitary body is relatively small. In the dinosaurs it was relatively large, and it is an interesting fact that in the huge sauropods it was very large. There was evidently a correlation between the enlargement of the pituitary body and the size of dinosaurs. The functions of the pituitary body in recent vertebrates are various, but among other things the anterior lobes of this gland, the very part of the pituitary body which seem
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Keywords: ., bookauthoramericanmu, bookcentury1900, booksubjectreptilesfossil
