l888.] NEW-YORK MICROSCOPICAL SOCIETY. 1 



and yet their origin, as well as that of the chitinous foundation 

 is sharply defined. 



The teeth He quite flat upon the horizontally extended radula, 

 with their points directed backwards towards the interior of the 

 mouth. And it is evident that the effective stroke of the organ 

 when acting upon food, must necessarily be the retracting stroke. 

 Huxley gives a vivid description of the action of the radula in 

 general, comparing this action to that of a chain-saw. The 

 muscles attached to either end of the radula cause it to travel 

 backwards and forwards over the upper surface, and, with a 

 sharp bend, under the lower surface of the forward end of the 

 skeleton, forming a most effective instrument for rasping any 

 substance with which the teeth are brought in contact. The 

 only chain-saw with which I am acquainted, is a surgical instru- 

 ment, consisting of a chain formed of links with rectangular 

 transverse section, having teeth along one of the narrow edges, 

 and a short, transverse handle at either end of the chain. In 

 action the chain is passed around a bone, or similar object, 

 with the teeth occupying the inner contour of the curve, and 

 then by an alternate pull of the hands of the operator these teeth 

 gradually sink themselves into the substance operated upon. 

 But the chain-saw of Sycotypus has the teeth upon the outer con- 

 tour of the curve, and, as the appropriate muscles cause the for- 

 midable weapon to travel over the end of the skeleton, we may 

 well believe the statement of Stimpson, that " with a sudden jerk 

 of the lingual ribbon, inward and sidelong, it can take a strip of 

 flesh " from any unfortunate mollusk on which it may be feeding. 



A METHOD OF PREPARING, FOR MICROSCOPICAL 



STUDY, THE RADULA OF SMALL SPECIES 



OF GASTEROPODA. 



BY CHARLES E. BEECHER. 

 {Read November iZth, 1887.) 



One of the early methods employed to obtain the lingual 

 membranes of Gasteropoda, was by actual dissection. This 

 process, in many cases, is very laborious and the results unsat- 



