Illustrated species account of Rissoa parva (da Costa, 1778) Identification and Biology (Mollusca, Littorinimorpha) and similar species. left) https://flic.kr/p/uxFKZK Costate form. 1: dark, non-costate, apical whorls nearly flat. 2: costate whorls convex.

Illustrated species account of Trivia monacha (da Costa, 1778) (Mollusca, Littorinimorpha). left) https://flic.kr/p/CEqony shell glazed. 1: shell height 11.2 mm. 2: columellar region a concave furrow. 3: slight mound marks position of enveloped apex.

Illustrated species account of Crepidula fornicata (Linnaeus, 1758) Mollusca, Littorinimorpha. left) https://flic.kr/p/iHTKuN Male on larger female. Reniform outline. Body whorl forms almost all of shell. Thin, wavy red-brown lines radiate from small