. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. Portion of the Pterygotus anglicus, Agassiz. 1. iliddle portion of the M Seraphim,1' or hack of the head, with the scale-like sculpturing. 2. Portion of the dilated base of one of the anterior feet, with its strong spines or teeth, nsed as masticating organs. 3. The proximal portion of one of the great anterior claws. 4. Termination of the same, with the serrated pincers. (See Agass., Poiss. Foss. du Yieux Gres Eouge, plate A.) . 1 and 2 are of the natnral size; 3 an
. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. Portion of the Pterygotus anglicus, Agassiz. 1. iliddle portion of the M Seraphim,1' or hack of the head, with the scale-like sculpturing. 2. Portion of the dilated base of one of the anterior feet, with its strong spines or teeth, nsed as masticating organs. 3. The proximal portion of one of the great anterior claws. 4. Termination of the same, with the serrated pincers. (See Agass., Poiss. Foss. du Yieux Gres Eouge, plate A.) . 1 and 2 are of the natnral size; 3 and 4 are reduced one-half. Fig. 591. Pterygotus anglicus. Ag., Forfarshire. Ventral aspect. Eestored by H. Wood- ward. , from nearly perfect specimens of allied species, found in the Upper Lud- low Eock of Lesmahagow. a. Carapace, showing the large sessile eyes at the anterior angles. o. The rnetastoma or post-oral plate (serving the office of a lower lip). c. c. Chelate appendages (antennules). d. First pair of simple palpi (antennce). e. Second pair of simple palpi (mandi- Mes). f. Third pair of simple palpi (first max- UUb). g. Pair of swimming feet with their broad basal joints, whose serrated edges serve the office of maxilla:. h. Thoracic or genital plate covering the reproductive organs (and probably also the branchiae), composed of two broad lateral ala?, and a slender median lobe, varying in form according to the sex. This thoracic plate covers the first two thoracic seg- ments, which are indicated by figures and a dotted line. 1-6. Thoracic segments. 7-12. Abdominal segments. 13. Telson, or The largest crustaceans living at the present day are the Inachus Kcempferi of De Haan, from Japan (a brachyurous or short-tailed crab), chiefly remarkable for the extraordinary length of its limbs; the fore arm measuring 4 feet in length, and the others in proportion,. Please note that these images are extracted from scanned page images that may have been digital
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectgeology, bookyear1868
