Stylochus neapolitanus (Delle Chiaje, 1841 –1844) Lang, 1884

Synonymous: Planaria neapolitana Delle Chiaje, 1941 .

Material examined. Two mature specimens, collected in Los Urrutias (Mar Menor, Murcia). From rocky substrate and Caulerpa prolifera found between 0.2 to 2 metres deep; Fig. 1 (8).

Morphological remarks. Male copulatory system with simple seminal vesicle; the ejaculatory duct runs straight to the base of the prostatic vesicle, where it joins the prostatic duct and forms the penis papilla. Gonopores separated. Simple female system without Lang’s vesicle. The specimens agree with the description and figure of Lang’s Stylochus neapolitanus (1884), except for one difference: S. neapolitanus only has marginal eyes in the anterior edge, but one of these specimens have them around the entire body edge. Such phenotypic variation in the distribution of the eye spots have been reported by Meixner (1907).

Distribution. Western Mediterranean Sea: Delle Chiaje 1841 (Sicily); Lang 1884 (Naples); Novell 2003 (Cap de Creus). Laidlaw (1906) cited it for the Cape Verde Islands, but Palombi (1939) later assigned that specimen to Stylochus castaneus .