Fig. 1 in Morphogenetic gradients in graptolites and bryozoans

Fig. 1. Astogeny in Graptolithoidea. A–C. Early development of a rhabdopleurid pterobranch and a tuboid graptolite colony. A. Encapsulated larva after metamorphosis (A1) and primary zooid in Rhabdopleura compacta Hincks (A2). B, C. Comparison of sicular portions in Recent Rhabdopleura compacta (B) and in Ordovician tuboid graptolite Epigraptus Eisenack (C). D. Sicula (D1) and thecae with underlying stolon system (D2) of an Ordovician dendroid graptolite Dendrograptus sp. E. Zooidal tubes and internal stolon system in Recent Rhabdopleura normani Allman. Not to scale. A, B, from Stebbing (1970), C–E, from Kozłowski (1949, 1970).