 ... fig. 1. Gabb's original description is as follows: "Shell thick, subglobose, equivalve and nearly equilateral ; beaks large, incurved, central, approximate, with sides sloping downward, anterior and basal margins regularly rounded ; posterior end...  Palæontology - Seite 199von Geological Survey of California - 1864 - 299 SeitenVollansicht - Über dieses Buch
 | California Academy of Sciences - 1917 - 512 Seiten
...basal margins regularly rounded ; posterior end rounded, or subtruncate, surface marked by 36 to 40 radiating ribs, very regular in size, a little the...teeth largest and most widely separated. Area very short and narrow." The radiating ribs in the young are usually narrower than the interspaces, while... | |
 | Albert B Reagan - 1917 - 476 Seiten
...basal margins regularly rounded; posterior end rounded, or subtruncate, surface marked by 36 to 40 radiating ribs, very regular in size, a little the...teeth largest and most widely separated. Area very short and narrow.” The radiating ribs in the young are usually narrower than the interspaces, while... | |
 | California Academy of Sciences - 1917 - 550 Seiten
...basal margins regularly rounded ; posterior end rounded, or subtruncate, surface marked by 36 to 40 radiating ribs, very regular in size, a little the...teeth largest and most widely separated. Area very short and narrow." The radiating ribs in the young are usually narrower than the interspaces, while... | |
 | California Academy of Sciences - 1917 - 518 Seiten
...basal margins regularly rounded ; posterior end rounded, or subtruncate, surface marked by 36 to 40 radiating ribs, very regular in size, a little the...teeth largest and most widely separated. Area very short and narrow." The radiating ribs in the young are usually narrower than the interspaces, while... | |
 | California Academy of Sciences - 1917 - 538 Seiten
...basal margins regularly rounded ; posterior end rounded, or subtruncate, surface marked by 36 to 40 radiating ribs, very regular in size, a little the...coarsely crenulated. Hinge robust; teeth arranged racliately, the lateral teeth largest and most widely separated. Area very short and narrow." The radiating... | |
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