“Hyalopecten, gen. nov. Type, H. undatus V.
PLATE XVIII. fig. 5.
Shell compressed, thin, hyaline. Valves nearly equal, with concentric undulations or corrugations, affecting the entire thickness; margins simple; sculpture none, or consisting of fine radial lines on one or both valves, without camptonectes sculpture. Hinge-plate thin and nearly plain; auricles well developed, unequal; byssal notch distinct.
The possible relations of this group to Syncyclonema were discussed on page 63.
The species known to me are as follows: H. dilectus V. and B., from 1813 fath., off Martha's Vineyard; H. fragilis (Jeff.), from northern Europe and the Arctic Ocean, and off the U. S. coast, in 578 to 1525 fath.; H. undatus Ver., off the U. S. coast, in 1423 fath.; and H. pudicus Smith, off Marion I., in 1375 fath.”
(Verrill, 1897: 71)
