ASPLANCHNA EBBESBORNII (rOTIFER) 421 



The digestive system is composed of the mouth, buccal pouchy 

 pharynx, stomach, and the attached digestive glands. The 

 stomach is strongly ciliated. There is no evidence of an intes- 

 tine in embryonic life. The trochal disc is formed from early 

 proliferated ectodermal folds at the ventro-anterior end. The 

 embryo, at its greatest flexure, is completely bent on itself, and 

 the embryonic foot extends anteriorly over the stomodaeum. The 

 brain is formed by a solid ingrowth of ectoderm at the anterior 

 end, above the buccal pouch. 



The excretory system is formed on the ventrolateral sides of 

 the median line from excretory bands or rows of cells. These 

 bands begin at the ventroposterior end by the proliferation of 

 special cells derived from the ectoderm. The adult system on 

 either side consists of one main and two recurrent tubules. The 

 main tube has a number of small evaginated tags bearing cilia 

 on their interior. 



I take this opportunity to express my gratitude to Mr. George 

 T. Kline, the biological artist, for his helpful suggestions and 

 execution of the drawings and lettering. 



Columbia, Missouri, January 1, 1919 



JOURNAL OF Mf)nPHOLOGT, VOL. 33, NO. 2 



