Fig. 17.
Camerocrinus, reduced in size (as restored by Hall). This is a crinoid, or feather-star, of the Upper Silurian period, floating by means of a hollow balloon-shaped structure divided into chambers and formed of calcareous plates.
Examples of this sort of adjustment are found in other types of animal life. In the beautiful Portuguese man-of-war (Physalia) and its allies flotation is provided for by membranous or cartilaginous sacs or vesicles filled with air, and which are the common support of numerous individuals which hang from them (see Fig. 18). In some allied creatures the buoyancy required is secured by little vesicles filled with oil secreted by the animals themselves.
In each of these cases we have a skilful adaptation of means to ends. The float is so constructed as to avail itself of the properties of gases and liquids, and the apparatus is framed on the most scientific principles and in the most artistic manner. That this apparatus grows and is not mechanically put together, and that in each case the instincts and the habits of the animal have been correlated with it, can scarcely be held by the most obtuse intellect to invalidate the evidence of intelligent design.
Fig. 18.
The Physalia, or "Portuguese man-of-war" of the Atlantic, being a colony of animals provided with long tentacles used as fishing-lines, and hanging from a membranous float with a crest, or "sail," on the top, and a pointed end which, being turned from side to side, serves as a rudder.
3. Structures apparently the most simple, and often heedlessly spoken of as if they involved no complexity, prove, on examination, to be intricate and complex almost beyond conception. In nothing, perhaps, is this better seen than in that much-abused protoplasm which has been made to do duty for God in the origination of life, but which is itself a most laboriously manufactured material. Albumen, or white of egg—which is otherwise named "protoplasm"—is a very complicated substance both chemically and in its molecular arrangements, and when endowed with life it presents properties altogether inscrutable. It is easy to say that the protoplasm of an egg or of some humble animalcule or microscopic embryo is little more than a mass of structureless jelly; yet, in the case of the embryo, a microscopic dot of this apparently structureless jelly must contain all the parts of the future animal, however complex; but how we may never know, and certainly cannot yet comprehend.