206 



MR. R. H. BURNE ON THE 



the chief laminae are occupied by others of less height, consti- 

 tuting according to their size and position secondary, tertiary, 

 and quaternary series. 



The position and height of the different series are shown to scale 

 in the accompanying diagram (text-fig. 23). It is to be noticed 

 that of the quaternary series those only interposed between the 

 secondary and tertiary series are represented by definite laminae. 

 Those between the tertiary and primary, when they are repre- 

 sented at all (and they apparently are not in every case), are 

 indicated only by a row of minute papillae (text-fig. 23, p.), as 

 the whole quaternary series is in the Giraffe and certain other 

 Ruminants*. 



Text-figure 20. Text-figure 21. 



Text-fig. 20.— Papillae of rumen, X 2. 

 Text-fig. 21.— Cell of reticulum, nat. size. 



Text-figure 22. 



Specialised papillae of oesophageal gutter, nat. size. 

 ?., lamina of psalterium ; ces.g., roof of oesophageal gutter. 



Towards the oesophagus the laminae gradually fade away, and 

 are succeeded by rows of enlarged papillae similar in character but 

 not in size to those that cover the surface of all the laminae. Some 

 of these papillae are enormously developed (text-fig. 22) and form, 

 when the oesophageal gutter is closed, a coarse filter to prevent 

 unsuitable food from passing into the psalterium. 



Papillae similar to these, though fewer in number and smaller 

 in size, are present in the stomach of the adult Ox, at the entry 

 of the oesophageal gutter into the psalterium. 



# Garrod, Proc. Zool. Soc. 1877, p. 5. 



