| 释义 |
orthochoanite Palæont.|ɔːθəʊˈkəʊənaɪt|
Also Ortho-.
[f. ortho- + Gr. χοάν-η funnel + -ite1 2 a.]
A nautiloid cephalopod having a straight, very short septal neck; also, a member of the obsolete sub-order Orthochoanites, of which such necks were characteristic.
1898A. Hyatt in Proc. Amer. Assoc. Adv. Sci. XLVII. 364 The suborders..are as follows:..IV. Orthochoanites. The siphuncles small except in primitive forms and without deposits, or, if present, these are irregular and are gathered around the funnels. No endosiphuncles. The funnels are straight and the siphuncle is apt to be tubular. 1944E. O. Ulrich et al. Ozarkian & Canad. Cephalopods III (Geol. Soc. Amer. Spec. Papers, No. 58) 27 Some of the Canadian nautilicones have lamellar deposits within the camerae... Apparently they are not present in the holochoanites, but they are being found in many orthochoanites and cyrtochoanites of the Paleozoic and the Triassic. 1952R. C. Moore et al. Invertebr. Fossils ix. 342/1 The Cyrtochoanites have been found to include a very diverse assemblage of which some are closely related to ‘Holochoanites’ and others to ‘Orthochoanites’.
Hence orthochoaˈnitic a.
1905[see holochoanitic a.]. 1944E. O. Ulrich et al. Ozarkian & Canad. Cephalopods III (Geol. Soc. Amer. Spec. Papers, No. 58) 26 In all the coiled Canadian cephalopods, the siphuncle is orthochoanitic in structure, the septal necks being short and straight. 1964C. Teichert in R. C. Moore Treat. Invertebr. Paleont. K. 95/2 Kuhn..separated the straight, orthochoanitic nautiloids as a new ‘suborder’ termed Orthoceracea. Ibid. 174/2 Siphuncle large..; septal necks very short, orthochoanitic. |