No. 478] ODONTOPHORAL APPARATUS IN SYCOTYPUS 733 



with the musculature of the proboscis wall (Fig. 5, m. cup). There 

 is also a ring muscle entering into this muscle cup, which surrounds 

 the esophagus, but is free from it on the dorsal, though adherent 

 to it on the ventral side (Fig. 9, mm.). 



Below the cup are found very numerous white bundles of muscle 

 which arise, in part, from the cup, from the ring muscle, and also 

 from the proboscis wall with which they are continuous, and, in 

 part, from the fold of integument that surrounds the base of the 

 proboscis (Fig. 2, rph.). These bundles pass backward to mingle 

 with the musculature of the integument that extends back from 

 the head fold to the columellar muscle; some bundles may mingle 

 with the fibers of the columellar muscle. 



Thev serve on contraction to pull the wdiole proboscis back 

 within^he head fold. They might be called the retractors of the 

 proboscis. These retractors are supplied from the cerebral 



Since there cxi-i- a distinct M-t of ivtrador- ;it the base of the 

 proboM-i., and .in.v it. uall ha> in part a nni.rulature of longi- 

 tu.linal liber., it is nut <lilli<'nlt to nn.lcrsta.id how retraction is 



l>ackward and thr Inn.uitu.liuai filKi-. ..n contraction shorten it. 

 From dissections made upon specimens with retracted proboscis, 

 it seems that ordinarily there is no turning wrong side out of the 

 proboscis, the shortening of the proboscis itself, and the contraction 

 of the numerous retractors that nm into the head fold, together with 

 the flexion of the ])rob()scis. l)eiMg sufHcient to carry the organ 



