G14 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



from the mouth opening to the most dorsal portion of the suctorial 

 bulb is about 70 micra, the cavity of the bulb being 25 micra long 

 (Figure 4). The suctorial bulb is often in contact with the nerve 

 collar. 



The radula is borne on a roundish muscular mass 13 micra in 

 diameter. The radula sac is practically cylindrical and 12 micra in 



66. sue 



sacrad- 



•or. 



'-par. 80. 



Figure 4. Diagram to show relation of organs to the pharynx, bb.suc, 

 suctorial bulb; cav.buc, buccal cavity; oes., esophagus; or., mouth; par.so., 

 body wall; phx., pharynx; sac.rad., radula sac. 



diameter (Figures 3, 4, sac. rad.) ; it projects 10 to 15 micra from the 

 dorsal surface of the muscular mass. The total number of rows of 

 teeth is 33-35, of which 18-20 are in the radula sac ; in the posterior 

 end of the sac are the beginnings of from 2-4 more rows. Each row 

 contains eight teeth, the median tooth being absent, which gives 

 the following formula 3-1-0-1-3. The first lateral tooth (Figure 

 5 ^') is large and of a deep amber color ; it is seven micra long and 

 its greatest width is 11/2 micra. The lateral margin bears a wing- 

 like projection 1/2 micron wide. The median edge of the distal half 

 of the tooth is somewhat crenulated, producing the effect of a number 

 of minute rounded teeth. This crenulated margin comes into close 

 contact with the same region on the opposite tooth. Laterally there 

 are three small teeth, the marginals ; the first, though the largest of 

 the three, is not more than 3 micra long and one micron wide ; these 



