64 THE APODIDyE PART i 



enormously developed in accordance with the great 

 development of the limb they have to move. 

 They evidently correspond with the muscles already 

 described as running into the ventral parapodia of the 

 other limbs, that is with those which come from the 

 longitudinal muscle band. They radiate from the 

 sternal plate, i.e. from the remains of the ventral muscle 

 bands of the head segments. At the dorsal extremity 

 of the mandibles, we find the remains of the circular 

 muscles which (see Fig. 15, A) were so powerfully 

 developed in the trunk limbs, in two or three bands 

 running between the dorsal middle line and the 

 integument, where the last rudiment of the dorsal 

 parapodium has disappeared (see Fig. 8, A, d, p. 37). 

 The longitudinal muscles, attached to the integu- 

 mental folds between the limbs (see Fig. I5,j5), are 

 strongly represented, and probably serve both for 

 closing the mandibles and rotating them round their 

 longitudinal axes. 



The same description applies with but slight 

 modification to the muscles of the first maxillae, but 

 in this case, those of the ventral parapodium, though 

 strongly developed in comparison with those of the 

 ventral parapodia of the trunk limbs, are weak as 

 compared with those of the mandibles. Again, a 

 more distinct rudiment of the dorsal parapodium is 

 retained in the first maxillae than in the mandibles, 

 and into this rudiment a very long and tolerably 

 strong band runs, probably homologous with the 

 circular muscle bands shown in Fig. 15, A. The 

 powerful muscles which enable the first maxillae to 



