4 JOURNAL OF THE [January, 



Huxley, in his " Anatomy of Invertebrated Animals," states 

 that the Odontophorous Mollusks, in which division he includes 

 all which stand in contradistinction to the acephalous Lamelli- 

 branchs and Brachiopods, possess the radula, with the exception 

 of a very few genera, e. g., Tethys, Doridium and Rhodope. 



Tryon, in his " Structural and Systematic Conchology," says 

 "in a few Gasteropods the tongue is unarmed." 



Our admirable Government Report on " The Fisheries and 

 Fishery Industries of the United States " (Section I., p. 695 

 1884), makes an unfortunate slip in stating that the Conch is 

 not provided with a "file-like tongue." 



But our Conchs are not lacking in this armature. Here is the 

 radula, preserved entire in glycerine, of the identical specimen 

 of Sycotypus, whose shell is at present exhibited. The armed 

 portion is a little more than two inches in length, and about one- 

 eighth of an inch broad, at the flattened, distal end. And here 

 is the radula of Fulgur, preserved in the same manner, entire, 

 and quite closely agreeing in size and form with that of its 

 relative. 



Prof. Lankester, in " The Encyclopaedia Britannica," already 

 cited, gives an admirable longitudinal-sectional illustration of 

 the mouth-parts of a glossophorous mollusk, and in the accom- 

 panying explanation clearly describes the action of the radula 

 in life, /. e., the forward, effective portion of the organ rasps off 

 the food by an alternate backward and forward motion, caused 

 by the alternate rolling of a globular mass of cartilage firmly at- 

 tached to the under side of the bed of the radula, near the oral 

 aperture. And he adds, " But in many Glossophora [e. g., the 

 Whelk) the apparatus is complicated by the fact that the diver- 

 ticulum itself, with its contained radula, rests but loosely on the 

 cartilage, and has special muscles attached to each end of it, 

 arising from the body-wall ; these muscles pull the whole diver- 

 ticulum, or radular sack, alternately backwards and forwards 

 over the surface of the cartilage." 



This is very nearly the description of the organ and its action 

 in the species under consideration. In Sycotypus, the radula, as 

 usual, consists of an assemblage of transverse rows of chitinous 

 teeth, situated upon the upper surface of a thin, but very strong 

 chitinous ribbon, lying longitudinally in the floor of the long 



