THE BRITISH FOSSIL BRACHIOPODA. 333 



genera. Hancock says (' Phil. Trans.,' vol. 148, p. 806, 1859) that "the arras, or labial 

 appendages, are normally composed of a membranous tube or canal bearing a serai-carti- 

 laginous ridge. The latter stretched from end to end of the former, and gives support to the 

 fringe of cirri. As far back as the commencement of the spirals the arms are, as above stated, 

 but for the entire length of the lateral portions of the loop, where the arms are doubled 

 upon themselves, and where, of course, two tubes or canals might have been expected, 

 there is only one, the two having, as it were, coalesced. These large canals at the roots of 

 the arms are continuous with those of the spirals, and terminate in blind sacs, one on each 

 side of the oesophagus, close to the mouth. On making a transverse section of this part of the 

 arm, the enlarged terminal portion of the brachial canal is seen connected with the external 

 edges of the dorsal and ventral membranes of the loop ; and the pallial lobule, stretching 

 between the inner edges, forms a sort of flattened inner tube. This inner tube opens 

 widely into the perivisceral chamber, and is in fact a prolongation of this chamber, and 

 terminates at the anterior extremity of the lateral portion of the loop, forming what may 

 be designated the brachial pouches." . . . . " The cirri are undoubtedly contractile to 

 some extent, and are also endowed with the power of motion individually, as proved by 

 the observations of Mr. Barrett. It would appear likewise that the entire fringe of cirri 

 can be elevated or depressed, there being ample means provided for the purpose ; " he 

 adds the arms of Wold, cranium and Terebr. caput-serpentis are disposed in the same 

 manner as in Wald. australis, but in T. caput-serpentis the expanded portions of the arms 

 are without any apophysory support, and accordingly other means are provided to sustain 

 them ; also that the arms of Rhynclionella psittacea are totally destitute of calcareous 

 support except at their origin, where they are sustained by two hinge-processes or oral 

 laminae, the points of which reach as far forward as their external margins. Again, he says 

 (p. 810) that " in Linyula anatina the brachial organs are strong and fleshy, and rise from 

 the back of the pallial chamber in the usual manner ; they are entirely without calcareous 

 support, even at their origin, and form two spiral coils with six or seven turns each, 

 directed inwards and upwards." We must, however, refer our reader for more ample 

 details to the anatomical works already recorded. 



The food of the Brachiopoda consists of infusoria and other minute organisms. 



In a very interesting paper Herouard enters into many details on the aqueous 

 currents relating to the nutrition of the Brachiopoda, 1 and to this the reader is referred. 

 In his paper he also proposes a new grouping of the Brachiopoda. 



In conclusion we may remark that in some families Rhynchonellida, Strophomenida, 

 Productida, and others, these labial appendages are spirally coiled. In others, Terebratula 

 and Lingulidce, only at their extremities. It is also almost certain that these beautiful 

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

 floating nutritious particles and minute microscopical organisms to the mouth (which is 

 situated between the appendages at their origin), but are subservient to the functions of 

 1 'Journal de Conchyliologie ' (3 ser., t. xvii), vol. xxv, p. 229, 1877. 



