■44 " Art. 3.— T. Kai .maki : 



cilia, turning to account a large amount of mucus and the surface 

 tension of tlie water. The mechanism may perhaps be equal to 

 that of gliding, and the surface tension of the water serves for the 

 purpose of a substratum. The movements of the parasitic worm 

 -seem to be slower in comparison than those of tlie freely living 

 forms. This is, I think, due to a great amount of powerful mucus. 



Note on the Classification of the Maricola. 



Böhmig (5) was the first who founded a more rational classifi- 

 ■cation of the marine Triclads in general. According to the features 

 of the genital organs, he has at length distinguished seven well- 

 established genera into two families and five subfamilies as 

 follows: — 



1. Fam. Procerodidœ. 



i. Huhiam. Euprocerudiiije, Procerodes. 

 ii. Subfam. Cercyriniu, Subussowia. Cercyra. 

 iii. Subfam. ^licropharyngina^. Micropharynx. 

 '2. Fam. Bdellouridae. 



i. Subfam. Uteriporinic, Uterlporus. 

 ii. Subfam. i'Aibdellourinop, Bdelloura, Syncoelidium. 

 Later, lie (6) brought under the Procerodidae a new sul)fan]ily 

 Stummerina? for receiving a new genus Stummeria. 



Then, Wilhelmi (71, 73) published an important paper un 

 tlie marine Triclads, in wliicli he classifies them according to a 

 new system as in tlie following: — 



1. Fam. Procerochda'. Procerodes, Stummcria. 



2. Fam. Uteriporida', Uterlporus. 



3. Fam. Cercyrida\ Cercyra, Cerhussow'ta, Sahussowia. 



4. Fam. Bdellourida'. Bdelloura, Syncoelidiwn. 



5. Fam. Micro])liarvngidte. Micropharynx. 



As is seen above, the Procerodid-subfamilies instituted by 

 Böhmig were raised by Wilhelmi to the rank of distinct famiUes, 

 making use of some distinctive characters which do not appear to 

 me to be of more than subfamily value. Now, casting a glance at 

 •the features of the genital apparatus, it is brought out clearly that 



