210 Ludwig Böhmig. [373 



»Nous l'avons trouve sur des Fucus vesiculosus et des Ulva 

 intestinalis. « 



Durch das breit herzförmige Vorderende und die ziemlich scharf 

 ausgesprochene halsartige Einschnürung hinter demselben unterscheidet 

 sich PI. littoralis leicht von andern marinen Tricladen. 



Planaria (?) macrostoma Darwin ^ 1844. [? Cercyra macrostoma 



Hallez2 1892.] 



Ich gebe aus Darwins Beschreibung nur die für die Identi- 

 fizierung wesentlichen Stellen wieder: 



»External alimentary orifice situated in the posterior half of 

 body: mouth-sucker nearly subcyliudrical, bell shaped, very long.« . . 

 »Its base is united, in the middle of the body, to the three principal 

 branches of the intestinal cavity; the two posterior branches unite 

 and form a ring, enclosing the Space in which the mouth sucker and 

 its external orifice are situated. The three main branches receive 

 the moss-like subdivision of the intestinal cavity, which reach all round 

 nearly to the margin of the body. The main, medial, intestinal cavity 

 ends at the anterior extremity in a small, opake, wedge-formed mass; 

 on each side of which, nearly on the dorsal surface, a black ocellus 

 is situated. Between the lateral branches on each side of the medial 

 cavity, seven or eight internal spherical cavities lie, including opake 

 balls, which I presume are immature ova; the anterior ones were 

 most developed: they were not present in the smaller specimens, or 

 in all the full-grown ones. I was unable to discover any genital 

 orifice, though no doubt one or two exist: near the posterior ex- 

 tremity there was a colourless space, but I could not see any orifice. 

 Anterior extremity Square, truncate, with the edges thin and pre- 

 hensile; the animal attaches itself by this part, almost licke a leech 

 with its sucker, and thus drags its body: posterior extremity broadly 

 rounded. Above, faintly coloured brownish purple in Striae, with a 

 colourless space over the alimentary orifice. Length 0,2 ths (5 mm); 

 breadth 0,06 ths (0,13 mm) of au inch.« 



Chonos Archipel, Westküste von Südamerika; in Brackwasser, 

 unter Steinen, Darwin. 



Epithel. 



Die einschichtige Körperdecke der untersuchten marinen Tricla- 

 den wird, wenn wir von Bd. Candida absehen, vollständig oder doch 

 1 Darwin, 18, S. 247. 2 Hallez, 32, S. 128. 



