The doctrine of descent and Darwinism . nimals/* The Amphioxus which lives in thesand in shallow places on variouscoasts, and is daily caught by thou-sands at Messina for example, is fiveor six centimetres in length, and iscompressed after the manner of afish, pointed at both ends, and semi- f^- ^^- F^n-grown whilst alive. It possesses no trace of limbs,at the posterior end only a pair of minute membranousmargins, the indication of dorsal and caudal fins, and isso simple in its internal structure that it is usually,though inaccurately, termed a fish. Its skeleton islimited
The doctrine of descent and Darwinism . nimals/* The Amphioxus which lives in thesand in shallow places on variouscoasts, and is daily caught by thou-sands at Messina for example, is fiveor six centimetres in length, and iscompressed after the manner of afish, pointed at both ends, and semi- f^- ^^- F^n-grown whilst alive. It possesses no trace of limbs,at the posterior end only a pair of minute membranousmargins, the indication of dorsal and caudal fins, and isso simple in its internal structure that it is usually,though inaccurately, termed a fish. Its skeleton islimited to the noto-chord, and some minute cartilaginousrods at the mouth and gills. It has no brain, and,except a small ciliated sac, perhaps to be interpreted asan olfactory organ, no sensory apparatus ; the heart istubular. And thus between the lancelet and othertrue fishes there exists so wide a difference that thepossibility remains open that the fishes passed throughsome other course of than phases likethat of the 256 THE DOCTRINE OF DESCENT. Our knowledge of the genealogy of the fishes may belaid down in the following diagram :—? Dipnoi. TclcosteL
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Keywords: ., bookauthorschmidtd, bookcentury1800, bookdecade1880, bookyear1882
