Fig. 4 in New and unusual upper Llandovery graptolites from Arctic Canada

Fig. 4. SEM micrographs of Stomatograptus canadensis Lenz, 1988. A. Immature specimen with five pairs of thecae, with well−preserved, shallow ancora umbrella, GSC38916, Cape Phillips, Cornwallis Island, Nunavut, Canada, probably Cyrtograptus centrifugus–C. murchisoni Biozone; A1, stereopair enlargement showing sicula and ancora umbrella; A2, stereopair of obverse view of rhabdosome; A3, proximal view of the ancora umbrella, showing opening of prosicula. B. Rhabdosome with ten pairs of thecae and nematularium, GSC38917, Cape Phillips, Cornwallis Island, Nunavut, Canada, probably Cyrtograptus centrifugus–C. murchisoni Biozone; B1, enlargement of distal part of rhabdosome with nematularium, B2, latero−ventral view of rhabdosome.