Text-book of comparative anatomy . The divisions of the Bopyri<ln 296 COMPARA TIVE ANA TOM Y CHAP. and Cryptoniscidce contain parasites which are chiefly hermaphrodite with dwarfmales. Body of the female deformed. Bopyrus (sexes separate), Gyge, Entoniscus, Cryptoniscus. Order 3. Amphipoda. Body laterally compressed. In the typical Amphipoda only the foremost thoracicsegment is fused with the head, in the Caprellidce and Cyamidce the two anteriorsegments. The gills are found on the thoracic feet as pouch-shaped epipodialappendages. Where the abdomen is well developed it carries 6 pairs of b
Text-book of comparative anatomy . The divisions of the Bopyri<ln 296 COMPARA TIVE ANA TOM Y CHAP. and Cryptoniscidce contain parasites which are chiefly hermaphrodite with dwarfmales. Body of the female deformed. Bopyrus (sexes separate), Gyge, Entoniscus, Cryptoniscus. Order 3. Amphipoda. Body laterally compressed. In the typical Amphipoda only the foremost thoracicsegment is fused with the head, in the Caprellidce and Cyamidce the two anteriorsegments. The gills are found on the thoracic feet as pouch-shaped epipodialappendages. Where the abdomen is well developed it carries 6 pairs of biramosefeet, of which the 3 anterior, generally more strongly developed, serve as swimmingfeet, the posterior, directed backwards and often stylet-shaped, as springing in the thorax with 3, seldom 1 or 2 pairs of ostia. Sub-Order 1. Crevettina. Head and eyes small. Foot-jaws with their limb-like feelers form a large underlip. Marine forms : Corophium, Talitrus, Orchcstia (Fig. 197), Lysianassa. In freshwater, FIG. 200.—Squilla, from the side, cth, Cephalo-thoracic shield ; VI, VII, VIII, the 3 posteriorfree thoracic segments ; ara7, the segments of the abdomen ; «7, the telson ; cm, eye ; «i, anterior ;H2, posterior antenna; 1-8, the 8 thoracic feet, of which 1 is the 1st foot-jaw and 2 is the 2d foot-jaw or the large seizing foot, 3, 4, 5 are the posterior seizing feet, 1-5 are called oral feet, 6, 7, 8,the 3 biramose rowing feet of the 3 posterior thoracic segments; p, penis ; Pi-pe, the pleoporta(swimming feet), p$ forming with the telson the powerful caudal fin ; br, the branchial tufts onthe exopodites of the pleopoda. Sub-Order 2. Hyperina. Head and eyes large, the latter often divided into frontal and lateral eyes. Footjaws form a small lower lip without feelers. Marine forms : Hyperia (eyes not divided),Phronima, Platyscelus, Oxyccplutlus. Sub-Order 3. Lamodipoda. Abdomen truncated. The 2 anterior thoracic segments fused with the head. Gillson
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanatomycomparative
