| 释义 |
prosiphonate, a. Zool.|prəʊˈsaɪfənət|
[f. prō, pro-1 1 a + siphon + -ate2 2.]
Of a chambered shell: Having the siphonal funnel directed forward, as in the Prosiphonata, a primary group of chambered cephalopods now extinct.
1935Twenhofel & Shrock Invertebr. Paleont. ix. 378 Prosiphonate ones [sc. septa] are found in Mesozoic forms [of cephalopod]. 1952R. C. Moore et al. Invertebr. Fossils ix. 371/1 In late Paleozoic and Mesozoic ammonoids, this structure [sc. the siphuncle] is mostly confined to immature stages, and forward-pointing septal necks appear in submature whorls. This condition is described as prosiphonate. 1970R. M. Black Elements Palaeont. viii. 86 Short septal necks encircle the siphuncle where it passes through the septa; the septal necks project forwards (prosiphonate) in the later formed septa of Mesozoic ammonites. |