30 
To the genus Ceratoplana I give the following diagnosis: 
Leptoplanids with somewhat elongated, anteriorly widened, poster- 
iorly narrowed body. Well-developed, long tentacles. Mouth situated 
far back in the centrally located, very long pharyngeal pocket. Few 
non-anastomosing intestinal coeca. True vesicula seminalis directly 
back of pharynx opening into a well-developed, unchambered pro- 
state vesicle. Penis long, narrow, and unarmed. Two genital 
apertures near each oiher but at a decided distance from the post- 
erior margin of the body. Vagina short. Ductus vaginalis present. 
Both canals open into a common antrum femininum. 
II. 
A Stylochidean Polyclad with Ductus genito- 
intestinalis. 
(Plate II). 
In the previous report I have dealt with the representatives of 
a new Leptoplanid genus, Ceratoplana^ which Dr. Th. Mortensen 
has collected underneath the sea-urchin C olob ocentr otus atratus L., 
both in Hawaii and in the Sunda Strait^ Together with the 
specimens of Ceratoplana colobocentroti var. hawaiiensis there 
was found also a representative of another Polyclad family, Styl- 
ochidae. When first sorting out the collection, I supposed that it 
was merely the question of a species of the widely spread genus 
Stylochus. But a later, more thorough examination disclosed cha- 
racteristics that did not quite harmonize with that opinion. The 
tentacles were too mueh reduced, being hardly discernible; the 
genital pores, although rather close to each other, were too far 
removed from the posterior margin of the body; the pharynx was 
rather short. In addition, a pair of false seminal vesicles, distinet 
and of a large size, was detected, when the specimen was mounted 
in oil of cedar. A series of sections through the genital apparatus 
was then necessary and the following examination not only verified 
the assumption as to a new genus but also brought about the quite 
unexpected discovery of a ductus genito-intestinalis. Such a con- 
nection is extremely rare in the whole Polyclad group, among all 
