No. 478] ODONTOPHORAL APPARATUS IN SYCOTYPUS 725 



natural state the rami are closely approximated for most of their 

 course, and form the doubly grooved roadway for the retractors 

 of the lingual ribbon. 



Retractors axd Protractors of the Odontophoral Car- 

 tilage — Their Nerve Supply 



Retractors. — These are two flat muscles which arise from the 

 posterior extremities of the rami of the cartilage, and pass back 

 ■one on each side to mingle with the fibers of the muscle cup at the 

 base of the proboscis (Fig. 9, re). They serve to pull the cartilage 

 — the whole buccal mass in fact — backward. 



Their nervous suppli/ comes through the stout nerve from the 

 buccal ganglion (Fig. 10, o). 



Protractors. — The protractors of the cartil.iut' arc coii^picnous 



from the lateral edges of the rami and pass forward to be mserted 

 into the ventral wall of the proboscis along two i)arallel hnes, 

 (Figs. 10, 11, pre). Besides these bands there r^ also a pair of 



