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Hamulus
The genus
Hamulus was proposed by Morton for small, unattached, tapering, curved calcareous tubes, with external ribs, distinct "volutions", and circular apertures, found in Cretaceous deposits on the Atlantic coastal plain of the United States. The tube of the genotype,
H. onyx, was described as having "six elevated, angular, longitudinal ribs extending from base to apex."
Morton compared
Hamulus with
Dentalium and
Serpula, stating that its tubes differed from the tubes of those genera in their "constant involuted form." He figured two tubes of
H. onyx. The first (his pl. 2, fig. 8) came from Lynch's Creek, South Carolina. It has probably been lost. The second (his pl. 16, fig. 5) was from "the older Cretaceous deposits at Erie, Alabama"; and he stated that he had also "a small individual from New Jersey." He assigned to his new genus the tubes which Münster had named
Serpula sexsulcata (see Goldfuss, Petrefacta Germaniae, 1826, p. 238, pl. 70, figs. 13a, b).
