Alcha evelinae Marcus, 1949

(Fig. 3 C–D)

Material and distribution in Cuba. Observations on live animals, whole mounted afterward. One whole mount from Siboney (April 4, 2017), on Gracilaria sp., 0.3 m depth, salinity 34 ‰. Five whole mounts from Bueycabón (February 6 & 21, 2018), on leaves of Thalassia testudinum and Syringodium filiformis, 0.5 m depth, salinity 33 ‰. All reference material in HU (VIII.3.05–VIII.3.10).

Remarks. The habitus and the internal organization of the studied specimen do not deviate from those mentioned in the original description by Marcus (1949) and by Karling & Schockaert (1977), including the typical blue pigmentation (Fig. 3D). The prostate stylet type III (Fig. 3D) of the Cuban specimens is 31–39 µm long (x̄ = 35 µm; n = 6), which is within the range mentioned in literature: 33–53 µm (Marcus 1949; Karling & Schockaert 1977; Jouk & De Vocht 1989; Artois & Tessens 2008).