... protoconch, color, and microsculpture. the protoconch revolution With their accretionary growth, gastropod shells typically exhibit at their apex a protoconch secreted by the embryo or veliger larva before hatching or metamorphosis ...
... protoconch at the apex together with the initial phase of the teloconch . The protoconch or larval stage has a diameter of 0.24 mm and is delim- ited from the teloconch by a narrow incision . On this and a second specimen ( pl . 2 , fig ...
... protoconch reticulate - Continued . Axial sculpture not well developed before the final half turn ; spiral sculpture exceedingly feeble : Whorls of protoconch about 41⁄2- Whorls of protoconch 3 to 31⁄2- Whorls of protoconch 2 to 21⁄2 ...
... Protoconch ( Figure 1A ) The protoconch is almost globe - shaped , or slightly elongated along the axis , its maxi- mum diameter being about 0.3 mm . The wall of the protoconch consists of the principal prismatic layer , coated on the ...
... protoconch , viewed from the side , below and in front . FIGS . 4-5 . Apex and protoconch of another specimen . FIGS . 6-8 . Orthoceras politum , Klipst . Apex of conch and protoconch viewed from the sides and below . a , protoconch ; e ...
... protoconch , viewed from the side , below and in front . FIGS . 4-5 . Apex and protoconch of another specimen . FIGS . 6-8 . Orthoceras politum , Klipst . Apex of conch and protoconch viewed from the sides and below . a , protoconch ; e ...
... protoconch , i . e . , the first volution , is of the same type in the majority of living gastropods , being a simple smooth and umbilicated coil , with the tube gradually enlarging , and with the aperture nearly circular , and ...
... protoconch , i . e . , the first volution , is of the same type in the majority of living gastropods , being a ... protoconch . The Eocene Clavilithes and the Cretacic ( ? ) to modern Latyrus and Pur- pura are more distantly related to ...
Amadeus William Grabau. these hard parts , i . e . , the protoconch , should preserve primitive characteristics which a large number of related types have in com- mon . As I have repeatedly emphasized , the earliest stage of the protoconch ...
... protoconch , i . e . , the first volution , is of the same type in the majority of living gastropods , being a ... protoconch . Eocene Clavilithes and the Cretacic ( ? ) to modern Latyrus and Pur- pura are more distantly related to Fusus ...