Genus Metapolymorphina


Metapolymorphina McCulloch, 1977


Descrption: Genus Metapolymorphina differs from genus Polymorphina, type species P. burdigalensis (d’Orbigny, 1826) in being a taxon with a large thick, heavy appearing test, much compressed, elongate, molded in appearance, about uniform in width and chamber structure from end to end showing numerous pairs of slight sigmoid, but much more embraced, chambers on one half or side of longitudinal axis, less so on opposite side; anterior end tapering into an angular, large radiate aperture with prominent dentition and a hyaline collar; periphery  rounded, gently lobulated.



Metapolymorphina charlottensis (Cushman, 1925)


Polymorphina charlottensis Cushman, 1925, p. 41, pl. 6, fig. 9; Todd and Low, 1947, p. A25, pl. 3, fig. 13.

Metapolymorphina charlottensis (Cushman, 1925); McCulloch, 1977, p. 196, pl. 85, figs. 4-7; Patterson, Burbidge and Luternauer, 1998, p. 7, pl. 3, fig. 8;


Description: Test large, tapering slightly from the broadly rounded initial end, compressed, with the periphery rounded: chambers comparatively few, irregularly biserial, peculiarly overlapping at one side; sutures fairly distinct but not depressed; wall smooth; aperture radiate. Length up to 2 mm or more; breadth 0.65 mm.


Remarks. McCulloch (1977) illustrated both the microspheric and megalospheric forms, showing the range of length: width ratio.


Distribution: The type specimen was collected in the Queen Charlotte Sound, British Columbia. In Puget Sound M. charlottensis has been recorded off Vashon Island.