About Littorina sitkana R.A.Philippi, 1846
This species of winkle, scientifically named Littorina sitkana R.A.Philippi, 1846, typically has around ten coarse spiral ribs on its final shell whorl, with fine spiral microstriae located in the gaps between these ribs. Occasional variations exist: the ribbing may be completely missing, or ribs may only be present at the base of the shell. The species Littorina sitkana is most easily confused with Littorina subrotundata. The most reliable way to tell these two species apart is by comparing the capsule gland of their pallial oviduct. The native distribution of Littorina sitkana covers the coasts of Siberia, Japan, and the Pacific coast of North America, ranging from Alaska all the way down to Oregon.
