BRITISH MARINE TURBELLA.RIA. 503 



L. atomata. Taking these facts into account, it may, perhaps, 

 be said that Oersted's and Jensen's specimens have as much 

 right to be classed in the same species as has Oersted's L. 

 atomata. 



For the future recognition of L. Droebachensis I quote 

 Jensen's diagnosis. 



Length 10 mm. Breadth 4 — 5 mm. Body slightly 

 narrowed posteriorly, rounded at both ends. Dorsal surface 

 red with scattered darker spots^ and with a longitudinal area, 

 down the centre of which runs a broken white line. Ventral 

 surface white. Four paired groups of eyes. Anterior groups 

 placed longitudinally, hinder group directed outwards and 

 backwards, composed of larger eye-specks. Mouth subcentral. 

 Penis styliform, hardened at its apex or for its whole length. 

 Vagina connected with the sperm otheca by a long duct 

 provided with a moniliform series of dilatations (Jensen [49], 

 pi. vii, figs. 10 — 14). 



B. COTYLEA. 



Family EURYLEPTID^. 



Cotylea usually provided with marginal tentacles. 

 Brain anterior, behind the tentacles. Mouth just 

 behind, rarely in front of the brain. Pharynx 

 directed forwards, cylindrical. Main-gut behind 

 the pharyngeal sheath. Male copulatory organ 

 simple, directed forwards, placed just behind or 

 beneath the sheath of the pharynx. A hard stylet 

 in the penis. Female genital pore between the 

 penis and the sucker. Eyes (1) in or round the 

 tentacles; (2) double cephalic group, sometimes 

 greatly elongated. 



Genus 30. — Prosthecer^eus, Schmarda.^ 



Body smooth, delicate. Pharynx bell-shaped. Main- 



1 Sclimarda, L. K., ' Neue wirbellose Thiere, beobaclitet und gesammelt 

 auf einer Reise urn die Erde, 1853—1858,' Bd. i, 1859. 



