A guide to the fossil invertebrate animals in the Department of geology and palaeontology in the British museum (Natural history) . Fig. 55.—Shell of a common Silurian Brachiopod, Atrypa reticularis. a,ventral or peduncular valve; &, dorsal or brachial valve. ,-Showsbilateral symmetry, and slightly greater size of ventral valve. MoUusca; but both the shell and the soft parts have reallya very different structure from those of the Mollusca. Somuch of the anatomy of the Brachiopoda as is important tothe student of fossils, is illustrated by the large coloureddiagrams in the
A guide to the fossil invertebrate animals in the Department of geology and palaeontology in the British museum (Natural history) . Fig. 55.—Shell of a common Silurian Brachiopod, Atrypa reticularis. a,ventral or peduncular valve; &, dorsal or brachial valve. ,-Showsbilateral symmetry, and slightly greater size of ventral valve. MoUusca; but both the shell and the soft parts have reallya very different structure from those of the Mollusca. Somuch of the anatomy of the Brachiopoda as is important tothe student of fossils, is illustrated by the large coloureddiagrams in the The two valves of the shell he on the back and front of10 & 11. the animal, not on its sides as in bivalve molluscs. Each INSECTS. BRACHIOPODA. 109 valve is symmetrical in itself, its right and left halves re- Gallerysembling one another. On the other hand, one valve is nearly larger than the other (Figs. 55 a and 60 a). By thelarger valve the adult animal is usually attached to rocks orother objects. In a few forms, such as Crania (Diagram 1),the valve is directly cemented to the rock by its own sub-st
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Keywords: ., bookauthorbr, bookcentury1900, bookdecade1900, booksubjectfossils
