Anatomy of certain Rotifers. 41 



or lip-like processes. On retercncc to fig. 2 it will at once 

 be evident that the real point of attachment of these bodies 

 is on the outer or ventral edge of each salivary receptacle. 

 In addition to this the same figure also shows a connexion 

 between the salivary receptacle (on the left side facing the 

 observer) and the gut. The connexion which exists on the 

 right side is not shown in the drawing, owing to the section 

 not being exactly transverse. 



In my opinion the series of complicated movements so 

 exactly described by Dr. Hudson is none other than the 

 opening and closing of these valvular bodies, to allow tlie 

 secretion to flow into the gut as food is passing, in order to 

 assist digestion. 



Prof. Williamson (5) mentions in his paper a structure 

 which seems to have eluded the scrutiny of observers ever 

 since. lie says, " Two or three pyriform glandular (?) 

 looking bodies are often attached to the base of the upper 

 stomach, near the constriction which separates it from the 

 lower one. . . . Not having been able to trace any ducts or 

 orifices passing from these organs to the viscera, I have hesi- 

 tated to assert their glandular character." Dr. Hudson does 

 not appear to have seen these bodies, as he fails to notice their 

 presence. 



I have placed in my illustrations a view of this group of 

 cells as seen in longitudinal section to confirm Prof. William- 

 son's discovery [vide fig. 8). At present I am unable to offer 

 any suggestion as to what function they perform, as I have 

 failed to find any opening into the gut. 



As to the presence of Mr. Gosse's ^' . . . little granular 

 body connected with the tip (of ihe foot) by a point, and 

 enlarging at the upper end, where it is connected with a small 

 globular vesicle," I liave been unable to discover a single 

 trace of its presence in section ; and in my opinion it does 

 not exist. 



Mastax. 



Melicerta ringens and M. conifera. 



From the earliest days of microscopical investigation the 

 mastax has, perhaps, of all the organs attracted the most 

 attention. Originally taken for a heart. Prof. Ehrenberg 

 clearly demonstrated its function in the early part of the 

 present century. At a later period M. ringens formed the 

 subject for a most detailed examination by Prof. Williamson, 

 his paper being illustrated with some excellent figures. Mr. 



