100 Marine Shells of the Western Coast of Florida 



Subgenus GRAPTACME Pilsbry and Sharp, 1897 

 Dentjilinin eboreiimi'^ Conrad PI. 20, figs. 132a, b 



Alt., 25 to 38; diam., 2 to 2.75 mm. Slender; evenly and mod- 

 erately curved; much reduced in diameter posteriorly; circular in 

 section; white, salmon-pink in fresh shells; surface shining and 

 polished, occasionally with opaque patches. Apical third of shell is 

 sculptured with about 20 exceedingly fine and delicate riblets which 

 fade into the smooth surface. Growth lines obscure. There is a 

 narrow and deep apical slit on the convex side, frequently lost by 

 wear and breakage; a supplementary tube is often present which 

 shows the typical deep, narrow slit. 



From one to six fathoms. 



Subgenus LAEA'IDEKTALIUMi'^ Cossmann, 1888 

 Dent.iliuin callipeplumi""' Dall 



Extreme alt., 62; diam., 5 mm. The shell is characterized by 

 strong and even curvature and rapid increase in diameter. Strong, 

 thin, polished, cream color, entirely lacking in sculpture; shallow 

 apical notch or indication of one on the concave side; section is 

 circular. 



Occasional fresh beach specimen. 



Family SIPHONODEXTALIIDAEi^^ 



Members of the three West Atlantic genera of this family are 

 mollusks of deep water. Their shells are not likely to be taken in 

 the course of general collecting. Prominent features resemble those 

 of the Dentaliidae. They live in soft mud or sand and the foot or 

 expanded disc, is capable of contracting to a slender stalk. Burrowing 

 is done by thrusting the conic foot downward, expanding it into a 

 disc, which forms an anchor. The shell is pulled down by contraction 

 of the foot muscle, and this process is repeated over and over. Solen 

 and Barnea use this same method of locomotion. 



^^2 Lat., ebur, ivory. 



^^* Lat, laevis, smooth. 



^"^ Gr., kalos, beautiful; Lat., peplus, skirt or shawl. 



^"^ Gr., siphon, a tube; dens, dentis, a tooth, tooth-shaped. 



