170 
Discostylochus Bock 1925, Ilyplana n. g., Leptostylochus n. g., and 
Kaburakia n. g. Finally I have included in the Family Bergendalia 
Laidlaw 1903, previously ranked as “Anhang" of the Family (cf. 
Bock 1913, Yeri & Kaburaki 1918). The genus agrees in most 
respects with conditions met with in this Family. The male appara- 
tus shows a similar structure and the same general plan but for 
the faet that there is added a duplicate organ before or behind the 
ordinary one. The female apparatus belongs to the same type as 
oceurs in the Stylochid-genera Cryptophallus and Kaburakia. The 
peculiar spiral ridge of the sh’ell duet is also met with in some 
Stylochid-genera. As deviating features there thus remains to be 
mentioned the supposed absence of tentacular rudiments and ten- 
tacular groups of eyes. An examination of a series of sections 
through the anterior end of Bergendalia, evidently not yet under- 
taken, might perhaps verify my supposition as to slight traces of 
such formations. A similar task awaits, as indicated above, a care- 
ful and industrious investigator of Limnostylochus, where vestiges 
of tentacular rudiments have not as yet been observed. 
To make the key more useful I have added a few characters 
other than those necessary for the establishment of the table. This 
undertaking will undoubtedly facilitate the recognition of the ge¬ 
nera. I have also done it with the purpose of giving a short and 
convenient resumé of the Family. 
