Identifier: lifehistoryofb00leig (
find matches)Title:
The life-history of British serpents and their local distribution in the British IslesYear:
1901 (
1900s)Authors:
Leighton, Gerald (Gerald Rowley), b. 1868Subjects:
Snakes ReptilesPublisher:
Edinburgh and London, W. Blackwood and sonsContributing Library:
American Museum of Natural History LibraryDigitizing Sponsor:
Biodiversity Heritage LibraryView Book Page:
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view book online to see this illustration in context in a browseable online version of this book.Text Appearing Before Image:onnection with sex must be con-sidered the two main factors in the production of thevarying colours of adders. Locality would seem tohave but little influence. The old female adder shown is a good example ofwhat was just mentioned—viz., the disappearance ofthe dark markings with great age. Slie measured 26;inches in length, so there was no doubt as to hermaturity, and the zigzag line is discernible only foran inch or two a short distance behind the neck.The young male is the smallest adder I have takenin the Monnow Valley, being 19f inches—equal proofof his youth in that locality, where the average lengthof males is two feet. All these considerations might apply to otheranimals, but in the case of reptiles there is anotherpoint to take note of, and that is sloughing. Hascasting the slough any effect on the colour variation ?Strictly speaking, I think not. That is, the colours arenot different after sloughing, but they are better seen.(The smooth snake is not here referred to.) TheText Appearing After Image:THE ADDER. 123 brightest coloured of all adders is a young male seenjust after casting his slough. So in the female thedull colour is seen more distinctly after sloughing.The slough obscures the true colour ; it does not aidor influence its production. 7. Pathological causes.—The possibility of some veryexceptional colouring being due to pathological orunnatural causes must not be overlooked. DiseaseNote About Images Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.