58 
to the rule in the case of the Acotyleans. In regard to Idioplana, I 
refer to my remarks in the paper of this series published next. 
The transversal efferent duets from the uteri run to the anterior 
part of the vagina. Each uterus has a long caudally directed as 
well as a short anterior limb. Oviducts run from the dorsal part 
of the body down to the uteri, entering them on their dorsal side. 
Text-fig. 17 Euprosthiostonium adhaerens. Schematic diagram of the genital apparatus: 
the figure being combined from several sagittal sections through the middle part of 
the body. 72 x. 
bm, basement membrane; ep, epidermis; eu, enlrance of the uteri into the 
vagina; mi, main intestine, from which projects anteriorwards the rudimentary 
unpaired gut branch; mv, muscle wall of the body (the dotted line is the 
interior limit of it); p, fleshy penis; ph, pharynx: php, pharyngeal pocket; 
prep, epithelium with granular giands; ps, penis sheath; pst, penis stylet; 
vacc, accessory vesicle of the male apparatus (the other lies above the semi- 
nal vesicle); vs, vesicula seminalis. 
Discussion of the new genus: Asyet the fam i ly Pros^/n'- 
ostomidae Lang 1884 contains only two genera: Prosthiostomum 
Quatrefages 1845 and Enchiridium Bock 1913. The former has a 
world-wide distribution in warm and temperate waters and contains 
many species. Lang included two anatomically examined species 
and six Stimpson’s species from Hongkong and Japan as well as 
one doubtful species, pellucidum (Grube). 7 more species were 
described between 1884 and 1912 (see Bock, 1913, p. 283), and 
then 2 new ones from the Bahama Islands (Bock 1913) and 4 
