| 释义 |
protegulum Zool.|prəʊˈtɛgjuːləm|
[mod.L., f. pro-2 1 + L. tegulum covering.]
In brachiopods, the embryonic form of the shell.
1891C. E. Beecher in Amer. Jrnl. Sci. XLI. 344 All brachiopods, so far as studied by the writer, have a common form of embryonic shell, which may be termed the protegulum. 1904Amer. Jrnl. Sci. CLXVII. 283 The protegulum of this species [sc. Stropheodonta perplana] is nearly circular. 1935Twenhofel & Shrock Invertebr. Paleont. viii. 269 Growth proceeds around the protegulum, mainly along the anterior and lateral margins of the two valves. 1959L. H. Hyman Invertebrates V. xxi. 531 Each valve begins as a minute plate, the protegulum, presumably composed of periostracum. 1973P. Tasch Paleobiol. Invertebrates vii. 263/2 The outer surface of the mantle flaps (lobes) became white and smooth, indicating initial shell formation (protegulum). |