OCR Text |
Show Thend Some scientists hold that the hu-irrn hu-irrn hnnd has been evolved from the fill. H bns been pointed out that, whether the "original hand" has been developed or degraded Into tho claw ov the wihg of the bird, tho wing of tho bnt, tho fin of tho walrus, wal-rus, the single hoof of the horse, tho double hoof of the goat, the triple hoof of tho rhinoceros, or the quadruple quad-ruple hoof of the hippopotamus, the farther back Is traced the ancestral the more closely does the membor resemble re-semble tho human hand with Its five fingers. One conclusion, logical enough, Is that nil of the higher vertebrates are descended from a common group ol ancestors having five-fingered ex. tremltles. The hand with five flngera, fossils show, must have existed in the age cf fishes before tho development of land animals. The Australian mudfish mud-fish has been called a living fossil nnd represents a transitional stage from tho water to the land form cf life. The fin of this fish resembles n fern leaf, bearing on each sldo a. number of slender, pointed appendages. appendag-es. It possesses four of these primitive prim-itive fins that seem foreordnlned to develop Into legs, nnd by their aid it often ralseB Itself from the bed of a stream. It hns been contended that had some of the mudfishes hnbttuolly employed em-ployed their fins as legs, tho midrib of the fin and such branches as proved prov-ed especially useful In the act of walking walk-ing would have been preserved and strengthened In their descendant, whllo the other branches would have been eliminated by disuse. Tho result, re-sult, It Is thought, would havo been a foot with a larger or smaller number num-ber of toes. Tho number five, which forms the origlnnl basis of subdivision of the feet and hands of nil tho terrestrial ter-restrial successors ot the mud-fishes must have proved most ndvnntngeouB for somo reason as yet undlscerned. Goodwin's. |