^24 



OUR COMMON BRITISH FOSSILS, 



coiled arms for locomotive purposes. Such was the 

 origin of the term Brachiopoda, or "arm-footed." 

 And, although Professor King endeavoured to change 

 the name to Palliohranchiata (or " mantle-gilled "), the 



• latter somehow has not " stuck." Suffice 

 it to say, therefore, that the long arms 

 of the Brachiopoda — so distinctive a 

 feature in their anatomy and physi- 

 ology — are only labial appendages to 

 the mouth, bringing food by means of 

 their currents, and air as well ; but 



Fig. lyo. — Z/;7^«/« , , 



(Silurian forma- arc ncvcr emplovcd as k)comotive 



tion). ^ ^ 



organs. 

 The young of the Brachiopoda^ like those of such 

 well-known bivalves as the common oyster, are free- 



tug. igi.—Lingtila Lewisii 

 (Silurian formation). 



Fig. 192. — LeJ>ta'Ha transz'crsalis 

 (Silurian). 



swimmers. In this stage they are believed by 

 some to show evidences of annelid affinity — ^just as 

 Mr. Harmer has recently demonstrated that young 

 Polyzoa show affinities with the Rotiferce. It is 

 interesting thus to see the hitherto unstudied stages 

 of. embryological development enabling the naturalist 

 to join hands across a space which the boldest investi- 

 gator would not have dreamed of half a century ago ! 



