‘Evidently an oversight. Manifestly impossible,’ that learned authority at once decided. (As Schlegel stands high as a scientific ophiologist, the misprint is pointed out for the benefit of future students.)
Thus lengths, as to the number of vertebræ, vary in species of the same genus, but not in ‘individuals of the same species.’ And this alone is sufficiently perplexing.
For example, we read in one work that a rattlesnake has 194 vertebræ, and in another that ‘it,’ viz. ‘a rattlesnake,’ has 207 vertebræ. Both equally correct, because two distinct species are described. Again, Dr. Carpenter, in his Animal Physiology (edition of 1872), gives a table of the vertebræ of various animals, in which ‘a python’ has 422 joints, while Owen gives ‘a python’ 291 joints, each learned anatomist having examined a different species. By these facts we comprehend what Schlegel intended to say.
The little constrictors caught their finches with five feet of body at their disposal. An anaconda, with five yards of body to work with, might with equal ease coil three opossums.
‘The skeleton of a snake exhibits the greatest possible simplicity to which a vertebrate animal can be reduced,’ says Roget. It is ‘merely a lengthened spinal column.’ It is ‘simple’ in the same way that botanists call a stem simple when it has no branches, or bracts, or leaves, to interrupt its uniformity. For this reason, having no limbs, and therefore none of those bones which in quadrupeds connect the limbs to the trunk, the spine is, in unscientific language, alike all the way down; ‘un corps tout en tronc.’ And because those two first joints of the spine which have no ribs attached to them are in form precisely like the other joints, physiologists tell us that a snake has ‘no neck.’ By way of simplifying matters we just now called those two joints an invariable neck. But in the way of cervical or neck vertebræ, however, we must bear in mind that a true anatomical neck, in the eyes of science, a snake has not. Some of the four-legged reptiles have a true neck, that is, they have cervical vertebræ which differ from dorsal, lumbar, etc. vertebræ, as we ourselves and mammals in general have; because four-legged reptiles have a breast-bone and limbs to support, and their neck varies in length. For example, a tortoise has nine cervical or neck joints, a monitor lizard six, and a salamander only one.
But so also do the necks of mammals vary very greatly in length, while all, without exception, are formed of seven joints, only seven vertebræ; a man, a whale, a giraffe, and a mouse possess each seven cervical vertebræ, different in form from the rest of the joints of the spinal column. We might say that in appearance a whale has no neck, but its seven neck joints are flat and close as seven cards or seven pennies, while those of the giraffe are extraordinarily prolonged; and in ourselves—well, of course, the reader will admit the perfection of symmetry in our own necks, and the seven joints, therefore, are precisely of the proper size.
While the spine of a snake is ‘simple’ in respect of its joints being all formed on the same plan, it is the reverse of simple in its wonderfully complex structure. Professor Huxley, in his delightful lecture, said that ‘the most beautiful piece of anatomy he knew was the vertebra of a snake.’ Professor Owen thus anatomically describes it: ‘The vertebræ of serpents articulate with each other by eight joints, in addition to those of the cup and ball on the centrum; and interlock by parts reciprocally receiving and entering one another, like the joints called tenon and mortice in carpentry’ (Anatomy of the Vertebrates, p. 54).
Front and back view of a vertebra.