Boston Journal of Natural History. Boston, Boston Society of Natural History., The illustration features three distinct representations of the species H. Thyroidus. At the top, a detailed depiction of a snail showcases its elongated body and coiled shell, emphasizing its spiraled structure. The middle section presents a top-down view of a more rounded, flattened shell, highlighting its smooth surface and symmetrical form. Finally, the bottom illustration reveals another shell with a pronounced curve, exhibiting a unique opening that distinguishes it from the others. Each specimen is labeled, providing a clear reference for identification and study, reflecting the intricacies of these mollusks.