The anatomy of Lucapina crenulata. 



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slight contraction are able to close the opening between the mouth 

 and pharynx. 



At the same time the split-like apertures on each side of the 

 lower projection open, giving free access to the great cavities be- 

 tween the digestive glands. I have not been able to determine whether 

 the food enters these cavities in this way or not but I think it does 

 as there is open communication into them. 



The anterior part of the radula has a thin cartilage-like wing on 

 each side (Fig. E, 5, Rad.c) which rests upon the radular supports 

 (Fig. J Rad.s), the radula being in the groove between them. From 



Fig. E. 1, 2, S single teeth of radula, 4 cross-section of anterior end of radula, 

 5 Eadula : Ex external row, Med middle rows, En inner row, Rad. c radula cartilage- 

 like wing. 



this point the radula is sheathed in a tube which runs down, back, and 

 to the right of the oesophagus (Fig. J Bad. t). The part of the 

 radula within the tube is very soft, especially at its growing point, 

 where it is bifurcated with globular ends. The soft posterior end is 

 folded back upon the older part in order to accommodate itself to 

 the shorter tube. The anterior end of this tube-like sinus is closed 

 by the intimate connection of the muscular fibers between the radular 

 supports, which prevents the blood, circulating freely in the tube, 

 from coming out into the mouth cavity. 



The teeth of the radula are of three kinds (Fig. E). The first 

 {Ex) on the outside are ribbon-like and somewhat curved. They are 



Zool. Jahrb. X\l. Abth. f. Morph. 3Q 



