'24 NOTES ON THE BRITISH JURASSIC BRACHIOPODA. 



The pedancle varies considerably in length among the 

 recent forms. In some species it is so short that it is 

 hardly observable outside the foramen, whilst in the 

 Lingnlae it attains and sometimes exceeds half a foot in 

 length. No doubt the same marked variability charac- 

 terised the fossil forms. 



The structure I next wish to direct attention to is the 

 calcareous or semi-calcareous loop or supports for the 

 cirrated brachial or labial appendages, which, as before 

 stated, have been improperly designated arms or feet. 

 This is by no means an easy task, and I am fully alive to 

 the difficulties which must necessarily meet me in trying 

 to make myself understood without illustrating my remarks 

 with numerous diagrams and actual specimens. 



The interior of the shell, with the exception of the 

 pallium or mantle which secretes it, and the small space 

 occupied near the beak by the digestive organs — so-called 

 liver — and muscles, is almost entirely filled up by the 

 labial appendages, which in reality are lateral prolongations 

 of the mouth. These are of considerable length, closely 

 coiled up, and fringed on one side with lateral processes or 

 cirri. 



It is almost certain that these beautiful appendages, by 

 means of their cirri and cilia, are not only instrumental in 

 carrying floating nutritious particles to the mouth (which is 

 situated between the appendages at their origin), but are 

 subservient to the functions of respiration. 



The food of the Brachiopoda consists of infusoria and 

 other minute organisms (10, p. 333). 



As might be supposed, in the classification of the 

 Brachiopoda into families and sub-families, genera and sub- 

 genera, palaeontologists attach great importance to the shape 

 and position of the loop which acted as a support, or par- 



