344 BULLETIX 120, UNITED STATES NATIONAL MUSEUM. 



to be SO. The most highly evolved members of division 6, C. ophU, 

 C. longa, and 0. segmentata, are found in Malaysia and eastern 

 Asia. It is in these species that the evolution of the genus culmi- 



nates, and in respect to the strange inhibition of division, character- 

 istic of the Opalinidae, we may say that the evolution of the family 

 culminates in C. segmentata. The other species intergrade in about 

 the order named. 



