Girard, C. F. (1854). in: W. Stimpson, Synopsis of the marine Invertebrata of Grand Manan: or the region about the mouth of the Bay of Fundy, New Brunswick. Smithsonian Contributions to Knowledge, 6 Art. 5: 1-67, tab 2, fig 16. Washington City 1854 [Vol 6: 27-28, plate 2, fig 16]