. The Cambridge natural history. Zoology. l82 CRUSTACEA EUCARIDA DECAPODA tioii to this rule is found iu the Droniiacea, the most primitive of the Brachyura, to be soon considered, in which not only the third maxillipede, but also tlie first pair of pereiopods may be developed as biramous oars, a condition taking one back to the. Fig. 124.—a, Zoaea, x 24, and B, Metazoaea, x IB, of Corystes cassivelaunus. Ab,Brd abdominal .segment; An, 1st antenna ; E, eye ; (t, gills ; J/, 1st maxillipede ; , last thoracic appendage. (After Guruey.) Mysis stage of the Macrura. Tlie Metazoaea (Fig. 124, B)
. The Cambridge natural history. Zoology. l82 CRUSTACEA EUCARIDA DECAPODA tioii to this rule is found iu the Droniiacea, the most primitive of the Brachyura, to be soon considered, in which not only the third maxillipede, but also tlie first pair of pereiopods may be developed as biramous oars, a condition taking one back to the. Fig. 124.—a, Zoaea, x 24, and B, Metazoaea, x IB, of Corystes cassivelaunus. Ab,Brd abdominal .segment; An, 1st antenna ; E, eye ; (t, gills ; J/, 1st maxillipede ; , last thoracic appendage. (After Guruey.) Mysis stage of the Macrura. Tlie Metazoaea (Fig. 124, B) has the rudiments of the thoracic limbs developed and crowded together at the back of the carapace; they are all laid down in their definitive forms, and the abdomen has the pleopods precociously developed. These Zoaeal stages are of course pelagic, but the Meta- zoaea next passes into the Megalopa stage (Fig. 125), in which the little crab forsakes its pelagic life and assumes the ground- habits of the adult; the Megalopa, which corresponds exactly to. 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 Harmer, S. F. (Sidney Frederic), Sir, 1862-; Shipley, A. E. (Arthur Everett), Sir, 1861-1927. London : Macmillan and Co. ; New York : The Macmillan Company
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Keywords: ., bookauthorsh, bookcentury1800, bookdecade1890, booksubjectzoology
