. Elementary text-book of zoology. WALDHEIMIA. 169 process. Through a hole in this process there projects a peduncle which fastens the animal to a foreign body, such as a rock. A side view of the two shells recalls the appearance of a Roman lamp, with the peduncle as a wick ; hence the Brachiopoda are sometimes termed Fig- 97-—Ventral (A) and Dorsal (B) Shell of Waldheimia Australis. (After Davidson.). a. Adductor. a, Adductor. a\ Apex. /, Loop. b. Ventral Adjuster. /, Septum. c, Divaricator. s, Socket. y, Foramen. 0, Peduncular Muscles. t. Teeth. Lamp-shells. The two shells are hinged upon ea
. Elementary text-book of zoology. WALDHEIMIA. 169 process. Through a hole in this process there projects a peduncle which fastens the animal to a foreign body, such as a rock. A side view of the two shells recalls the appearance of a Roman lamp, with the peduncle as a wick ; hence the Brachiopoda are sometimes termed Fig- 97-—Ventral (A) and Dorsal (B) Shell of Waldheimia Australis. (After Davidson.). a. Adductor. a, Adductor. a\ Apex. /, Loop. b. Ventral Adjuster. /, Septum. c, Divaricator. s, Socket. y, Foramen. 0, Peduncular Muscles. t. Teeth. Lamp-shells. The two shells are hinged upon each other at the posterior end (towards the peduncle) and can be widely opened anteriorly. The shells and the animal are piano-symmetric, about a perpendicular plane passing through the middle line of each shell. (The bivalve Mollusca are piano-symmetric, about a plane passing between the shells, which are therefore right and left, not dorsal and ventral.) Inside the dried dorsal shell can be seen a complex calcareous skeleton in the form of a twisted loop. The growth of the shell is like that of bivalves. The cavity inside the shells is lined by a soft double flap of the body called the mantle, enclosing the mantle-cavity. Its edge is fringed with setcE. The most conspicuous part of the body is the lophophore, which consists of a pair of coiled arms carrying a great number of ciliated tentacles. A ridge lying dorsal to the mouth, the epistome, is continued round the lophophoral arms. The mouth leads into a short oesophagus, a swollen stomach, and a short intestine which ends blindly. There is a pair of large racemose digestive glands, with ducts leading into the stomach. The coelom is spacious, and the same parts of the mesoderm. 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 Masterman, Arthur Thomas. Edi
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Keywords: ., bookcentury1900, bookcollectionbiod, bookdecade1900, bookyear1902
