SiPHONODENTALIIDAE AND GASTEROPODA 101 



Genus CADTJLUS Philippi, 1844 

 Cadnlus qnadridentatnsi" Dall PI. 45, figs. 315a, b 



Alt., 8 mm., greatest diam., about 1 mm. This tubular shell is 

 creamy white, smooth and glossy; slightly swollen above the middle, 

 contracting slightly toward the apex which is entire and unslit; 

 moderately curved, contracting rapidly to the posterior opening, 

 which has four triangular notches, formmg the four pointed teeth. 



Cadulus carolinensis Bush PL 45, fig. 316 



Alt., 10 mm., anterior opening, 1 mm., greatest diam., 1.5 mm., 

 posterior opening, .5 mm. Curved shell is bluish white, almost trans- 

 parent and shiny. Anterior opening round, oblique. Shell swells some- 

 what toward the middle, contracting gradually to a small, round 

 posterior aperture which has four shallow notches, forming four short, 

 rounded teeth. 



Class GASTEROPODA 



The Gasteropoda (Lat., gaster, stomach; Gr., pod-, foot), are 

 numerically the largest division of the Mollusca, and their shells 

 are the most varied in form. The animals are highly organized — all 

 have distinct heads and usually cephalic tentacles and structurally 

 complex eyes. The senses of touch and smell are highly developed. 

 Some gasteropods are unisexual, some are hermaphrodites and a few 

 are viviparous. Most of them deposit their spawn in capsules whose 

 shape IS characteristic of their species. In other cases, the ova are 

 extruded in a cordlike or ribbonlike matrix of gelatinous material. 



A curious structure possessed in common by the Gasteropoda, 

 the Amphineura and the Scaphopoda, is the radula or lingual ribbon. 

 This is a chitinous band within the mouth or pharj^nx having upon 

 its outer surface many, and usually small, teeth. The radula is moved 

 back and forth by special muscles or used with a gimletlike action. 

 It serves to pierce the shells of captured mollusks, to tear and shred 

 the food of the carnivorous, and as a rasp in case of the vegetable 

 feeders. This structure has no analogue in any other group of animals. 



^'^'^ Lat., cadus, small pail, jar; quatuor, four. 



