. Principles of economic zoo?logy. Zoology, Economic. BRACHIOPODA 49 The shell is only partially filled by the body, and the valves are lined by the mantle lobes, whose free edges are bristled. The mantle lobes enclose a large mantle ca\'ity. In the body is a spacious coelom, which is extended into the mantle lobes. The coelom contains the digestive tract, the liver, and the reproductive organs. The latter are chiefly in the mantle lobes. The digestive tract, which is bent much as in the Polyzoa, consists of gullet, stomach, and intestine. The mouth is surrounded by the tentacled lophophore or
. Principles of economic zoo?logy. Zoology, Economic. BRACHIOPODA 49 The shell is only partially filled by the body, and the valves are lined by the mantle lobes, whose free edges are bristled. The mantle lobes enclose a large mantle ca\'ity. In the body is a spacious coelom, which is extended into the mantle lobes. The coelom contains the digestive tract, the liver, and the reproductive organs. The latter are chiefly in the mantle lobes. The digestive tract, which is bent much as in the Polyzoa, consists of gullet, stomach, and intestine. The mouth is surrounded by the tentacled lophophore or " ; The inner surface of the tentacles is covered with cilia, which set up currents in the water and sweep minute animals and algae into the mouth for food. The heart, usually present, lies. Fig. 38.—Diagram of a brachiopod: b, Tentacles around mouth, m; i, intestine; the shell black, the stalk to the right. (Kingsley's "Compara- tive Zoology," Henry Holt & Co., Publishers.) dorsal to the stomach, to which it is attached. The nervous system con- sists of an esophageal ring. Sense organs are usually wanting in the adult. Important Biologic Facts.—For the first time, according to the classification used, a closed system of blood-vessels and red blood-corpuscles are found. The digestive tract has been developed into gullet, stomach, and intestine, and a liver also appears. The Brachiopoda were formerly supposed to belong to branch Mollusca. But the valves of the shell are dorsal and ventral, not right and left, while the tentacled lophophore, the character of the nephridia, and the modified trochosphere larva all tend to show relationship with members of branch Molluscoida. Classification.— Class. I. Polyzo'a. II. Phoroni'da. III. Brachi6p'oda. 4 Example. Bugula avicularia (Bird's-head Coralline). Phoronis. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - co
Size: 2270px × 1101px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublisherphila, bookyear1915
