. The Australian zoologist. Zoology; Zoology; Zoology. H. T. JOHNSON gastroliths, in aboriginal middens (K. Kefous and M. Smith, and P. J. F. Coutts, personal communications). Other decapods which are similarly preyed upon include the New Zealand freshwater crayfish, Paranephrops zealandicus, whose gastroliths have been found in perch, trout and shag stomachs (Scott and Duncan 1967). The gastroliths are a pair of hard rounded bodies which occur in some species of decapod crustaceans. They are located on the sides of the cardiac stomach, and make their first appearance in the early stages of th
. The Australian zoologist. Zoology; Zoology; Zoology. H. T. JOHNSON gastroliths, in aboriginal middens (K. Kefous and M. Smith, and P. J. F. Coutts, personal communications). Other decapods which are similarly preyed upon include the New Zealand freshwater crayfish, Paranephrops zealandicus, whose gastroliths have been found in perch, trout and shag stomachs (Scott and Duncan 1967). The gastroliths are a pair of hard rounded bodies which occur in some species of decapod crustaceans. They are located on the sides of the cardiac stomach, and make their first appearance in the early stages of the moult cycle (Travis 1960); they continue to grow to their maximum size, at which time moult occurs. The gastroliths are then cast off, together with the cuticular lining of the crayfish's stomach, wherein they come to lie. There they are dissolved, and their calcium store resorbed. During and for some time after moulting, the yabby, like all crustaceans, is most vulnerable to predation. Because the gastroliths are composed mainly of calcium salts, and are the least digestible part of the crayfish, they may remain in a predator's stomach for a considerable time. As the size of crayfish eaten is often of interest to researchers studying the feeding habits of a predator, I set out to find a way of determining the size of the crayfish from the size of its Fig. la. A fully developed gastrolith, split along the long axis, showing the disc and the lavered structure of the gastrolith. Scale unit is 1 cm. 436 Aust. Zool. 21(5), 1984. 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 Royal Zoological Society of New South Wales; Royal Zoological Society of New South Wales. Proceedings. [Sydney, Royal Zoological Society of New South Wales]
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1914
