. Annals of the Carnegie Museum. Carnegie Museum; Carnegie Museum of Natural History; Natural history. Fig. 33. Eutic'Ha /inckiccni llaW. Young specimen with open delthyrium. X 16. Fig. 34. The same species. An adult, showing several growth stages. XS- The first pair of punctre are .072 mm. from the beak and in front of them, on the median line, and .109 mm. from the beak, is a third one. Beyond this they are scattered sparingly o\er the surface for a short distance but toward the front of the shell they become very numerous. Changes During De'velopinent. Outline. —The outline changes very lit
. Annals of the Carnegie Museum. Carnegie Museum; Carnegie Museum of Natural History; Natural history. Fig. 33. Eutic'Ha /inckiccni llaW. Young specimen with open delthyrium. X 16. Fig. 34. The same species. An adult, showing several growth stages. XS- The first pair of punctre are .072 mm. from the beak and in front of them, on the median line, and .109 mm. from the beak, is a third one. Beyond this they are scattered sparingly o\er the surface for a short distance but toward the front of the shell they become very numerous. Changes During De'velopinent. Outline. —The outline changes very little during the various stages. There are both broad and narrow forms. The index of the ventral valve varies from .68 to .88 in young specimens and from .76 to .92 in adults. The dorsal valves of adults of the broad type are nearly cir- cular, while the index of the same valves in the narrow form is from .71 to .88. Convexity of Valves. —In young stages the ventral valve is slightly deeper than the dorsal, but in the adult the convexity of the valves is often reversed. The ventral beak extends straight beyond the hinge in young individuals. In adults the umbo is incurved and the apex of the beak is truncated by the pedicle opening. 'E. S. Morse, Alemoirs tioston Sor. A'af. //is/., \'ol. V. No. 8, 1902, pi. 62, fig. 15, A/ei>i. Bos. Soc. iVa/. //ist., Vol. II, pt. I, No. 2, pi. I, fig. 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 Carnegie Museum; Carnegie Museum of Natural History. [Pittsburgh] : Published by authority of the Board of Trustees of the Carnegie Institute
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Keywords: ., booka, bookcentury1900, bookdecade1900, booksubjectnaturalhistory
