. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 112 ANIMAL KINGDOM. compound eyes, more than four pairs of legs, the respiration effected by gills, and the shell generally hard and calcareous. These ento- moid aquatic animals are generally carnivorous, and have a short and straight alimentary canal. Their circulating system is often aided by a muscular ventricle. The sexes are separate, and the organs of generation are double and symmetrical in both sexes. Their biliary or- gans have a conglomerate form, being com- posed of minute glandular follicles grouped together
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 112 ANIMAL KINGDOM. compound eyes, more than four pairs of legs, the respiration effected by gills, and the shell generally hard and calcareous. These ento- moid aquatic animals are generally carnivorous, and have a short and straight alimentary canal. Their circulating system is often aided by a muscular ventricle. The sexes are separate, and the organs of generation are double and symmetrical in both sexes. Their biliary or- gans have a conglomerate form, being com- posed of minute glandular follicles grouped together into lobules and larger lobes. Some of these animals are fixed and parasitic, and breathe by their general exterior surface; most are free, and respire by means of branchiae placed under the sides of the carapace or ex- posed on the under-surface of the post-abdomen. (See CRUSTACEA.) The THIRD, or CYCLO-GANGLIATED or mol- luscous DIVISION of the animal kingdom, com- prehends five classes, viz.:— 14. Tunicata, soft, aquatic, acephalous animals, breathing by internal branchiae, never in form of four pectinated laminae, and covered by a close external elastic tunic furnished with at least two apertures. The exterior tunic is lined by a muscular coat; sympathetic ganglia are observed in the abdominal cavity, and the respiratory organs are ciliated as in higher molluscous classes for the production of the respiratory currents. The mouth, unprovided with tentacula or other organs of sense, opens at the bottom of the abdominal cavity, as seen in the cynthia dione. (Fig. 39. a.) The short cesopha- Fig. Fig. 40. gus leads to a capacious stomach (b), sometimes surrounded by the lobes of a small liver, which pours its secretion into that cavity as in higher mollusca. From the stomach a short wide convoluted intestine proceeds to near the ven- tral orifice (d*) of the sac, where it terminates in the anus (c). The thoracic orifice (e), or the entrance to the respiratory cavity, is g
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