AN UNDESCRIBED ACRANIATE. 215 



As the animal is small and translucent the course of food and 

 carmine granules may be traced through most of the digestive 

 tract. The strong current of water setting into the pre-oral cham- 

 ber seems to be controlled by the longitudinal, ciliated ridges of 

 Miiller's "Kaderorgan" which pass forward from the velum on 

 the inside of each lateral wall of the pre-oral chamber. Thus the 

 carmine granules pass rapidly along these ridges towards the velum 

 where they are turned inward towards the aperture, mouth, at the 

 centre of the velum. The granules pass along in strings as if held 

 together by a thin mucous ; once through the mouth they do not 

 pass out through the pharyngeal slits but continue along the 

 median dorsal pharyngeal groove, the hyper-pharyngeal groove, 

 still adhering to one another in strings. In actual longitudinal 

 and cross sections these strings of granules may still be recognized 

 in the ciliated hyper-pharyngeal groove. 



Explanation of diagram. The dotted line indicates the course of food passing 

 through the digestive tract which is divided into pre-oral chamber, pharynx, 

 stomach with diverticulum and first and second intestinal regions. 



This groove leads into what may be called the stomach within 

 which the current of granules, or the granule containing mucous 

 strand, turns abruptly downwards and forwards as indicated in 

 the above diagram, yet does not enter the diverticulum but, still 

 under the control of the active cilia lining the digestive tract, passes 

 back again through the centre of the stomach. It is now revolving 

 rapidly in a constant direction from right to left and continues to 

 do so throughout the next division of the digestive tract, the first 

 or larger section of the intestine. In this part of the intestine the 

 granules, diatomes, etc., collect into clumps separated by the clear 

 part of the continuous mucous-like strand. In this region the 

 intestinal epithelium is especially modified in a zone that became 

 very prominent when staining reagents are used. 



The second, final and smaller part of the intestine, contains pellets 

 of detritus that become successively larger towards the anus where 



