'296 TKAXS ACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



L.t.h.). These are extremely importaut structures, and 

 run back a cousiderable distance, to branch finally and 

 become attached to the tioor of the proboscis. They will 

 be termed the Lateral odontoplioral hands. These bands 

 form the meeting place at their anterior extremities for 

 a number of dorsal and ventral muscles and the odonto- 

 plioral cartilage. Thus many of the muscles of the 

 radula are not attached to the walls of the proboscis 

 directly, but to two lateral musculo-connective tissue 

 bands. Neither Geddes nor Oswald have figured this 

 muscle connection with the lateral bauds correctly. 



The odontophoral cartilage is formed of two long 

 band-like lateral cartilages, which are much thicker at 

 their anterior ends and somewhat L-shaped in section. 

 They fuse ventrally at their anterior ends, and thus by 

 reason of their shape form the walls of a gutter or groove 

 open dorsally (figs. 20, 18 and 23). In addition, they 

 are united posteriorly by the sheet of transverse muscle 

 fibres, the companion structure to the dorsal sheet already 

 noticed (fig. 18, V.e.m.). 



Upon this odontoplioral cariilage lies the radula. 

 Tliere is usually aliout 20 mm. of it on the dorsal surface, 

 and 10 mm. on the ventral. 



The muscles of the odoiitojjliore may be divided 

 into : — 



I. Muscles atlachcd to laduhi, (a) dorsally, and 

 (6) ventrally; 

 II. Muscles attached to o(lunto}»horal cartilage; 

 or 



I. Protractors, {a) of Pharynx, and (?>) of 



lladula and Caitilage. 

 II. detractors, {(t) dorsal, and (J>) ventral. 



The i)t()tra(;tors of the Pliarynx consist of two 

 muscles which run doisall\- from the anteiior end of tlie 



