Page:Popular Science Monthly Volume 9.djvu/600

574 of lowly, creeping things of earth that do not attain to the dignity of lungs! There is a saving of time, too, for the blood is made arterial while on its journey, and thus travels direct (without the delay of passing off to special pulmonary organs) to the performance of its functions, removing, replacing, renewing, sustaining, building up, absorbing. Having accomplished these, and become as it were venous, it passes into the intervisceral spaces, and there, receiving an increment of fresh globules, the products of digestion, completes its circuit by returning through distinct valvular openings into the dorsal vessel from which it was first distributed. "Among the Chilognatha," says Siebold, "the Iulidœ are noticeable for the very simple character of their trachean apparatus; their air-canals neither ramify nor anastomose. With the Glomerina the tracheæ are branched, but do not anastomose; but those of the Chilopoda are very ramose, and their large trunks intercommunicate at their origin by longitudinal and transverse anastomoses, so that each stigma can introduce air into the entire trachean system." It was chiefly with the view of drawing attention to this last-mentioned fact (a most striking evidence of design), to this remarkable example of the exquisite adaptation of the creature's construction to the condition of existence ordained for it by the Creator, that I began this bit of simple gossip about Geophilus. In his subterranean career he constantly meets with accidents which link him up in sympathetic association with Brunel and Stephenson, and the Bedouin of the desert. He never bored a practicable highway beneath the bed of Isis, nor made firm the foundations of an iron road across the quaking surface of Chat Moss; neither has he braved the burning sand-blasts of the simoom; yet in his degree he has met with such like critical experiences a hundred times.

One day the roof of his tunnel crashed in upon him, and buried a dozen of his segments, squeezing the very breath out of them; on another day the rain had saturated the rubbish-heap he was toiling in, a score or two of his somites were under water, and he had to "batten down" the stigmata belonging thereto to save those portions of himself from drowning; and yet, again, in the scorching dog-days, a hot wind swept the earth, and a dry and thirsty clod, crumbling away, discharged an avalanche of dust which overwhelmed nine-tenths of him. In each and all of these catastrophes his life would not have been worth ten seconds' purchase, even with his many spiracles, but for the anastomosing branches of his windpipes, the cross-rungs of his air-ladder, which enabled the air received by the unchoked segments to pass in every direction through the whole system. That there is perfectly free communication from any one spiracle to the whole network of air-passages may be seen by examining the figure which I have given; and if any reader has still a doubt on his mind he may remove it, if he is a dexterous manipulator, by dissecting out the tracheary apparatus of the first chilopodous Myriapod he can lay hands on;