. Cassell's natural history. Animals; Animal behavior. from the adult than in others of the long-tailed Crustacea. They are, however, sufficiently important to mention (Fig. i'i). The eyes of the young Lobster are sessile, not mounted upon eye-stalks. The long antennae are not seen, nor the beak or rostrum. The thoracic feet are rudimentary. The abdominal feet are entirely absent, as in the young Crab. At a later moult the jointed thoracic limbs are seen, and the antennje begin to be developed. The hind body, or abdomen, is, however, still without appendages, and the eyes without eye-stalks. S
. Cassell's natural history. Animals; Animal behavior. from the adult than in others of the long-tailed Crustacea. They are, however, sufficiently important to mention (Fig. i'i). The eyes of the young Lobster are sessile, not mounted upon eye-stalks. The long antennae are not seen, nor the beak or rostrum. The thoracic feet are rudimentary. The abdominal feet are entirely absent, as in the young Crab. At a later moult the jointed thoracic limbs are seen, and the antennje begin to be developed. The hind body, or abdomen, is, however, still without appendages, and the eyes without eye-stalks. Still later these ab- dominal feet make their appearance. In estimating the greater or less extent of metamoi'phosis undergone by the young of any Crustacean in its passage to the adult animal, it is necessary also to take account of its embr}'- oiiic development, for many species, both of the Podophthalmia (or stalk-eyed) and Edriojihthahnia (or sessile-eyed) Crustacea undergo these larval changes in the egg, whilst others (as A sellus and Mysis) do .so in the incu- batory pouch of the mother. The Norway Lobster {Nephroj^s norveyiciis, Fig. 24) occurs on both the English and French coast, as well as on that of Norway, and extends as far south as the Mediterra- Fig. 23.—YOUNG LOBSTERS. nean. The body of this elegant species is long, and the segments extremely cylindrical in form; the cephalo- thorax is compressed at the sides. The great claws are long, slender, spiny, and ridged strongly down the centre; the rostrum is long and slender. The scale at the outer base of the antennae is large. The eyes are large and prominent The colour of this Lobster is much paler than that of Ilomarus, and there are bands of darker colour on the body-rings. There is only one species known. The Common River Cray-fish {Astacus jluvialilis), a fresh-water genus, was separated by Milne-Edwards from the Lobsters, and may be readily known from others by the rostrum or beak having a small tooth on eac
Size: 1808px × 1383px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjecta, booksubjectanimals
