184 Marine Shells of the Western Coast of Florida 



tion of the outside. The first two nuclear whorls are smooth, followed by 

 a turn in which there are moderately strong, retractively curved axial 

 riblets, which are about as wide as the spaces that separate them ; follow- 

 ing this is the postnuclear sculpture. Postnuclear whorls with a spiral 

 cord immediately below the summit and a broad tuberculated cord im- 

 mediately above the suture. The latter is marked by a secondary cord, 

 which coincides with the crest of the tubercules and a little heavier one 

 immediately anterior to the major portion of the tubercules. This on the 

 early turn falls into the suture, but on the last whorl is slightly posterior 

 to it. Of the tubercules twelve are present on the first of the postnuclear 

 turns, ten on the second, third, and fourth, eleven on the fifth and sixth, 

 and six on the last half of the last turn. In addition to the above sculpture, 

 the entire spire and base are marked by numerous, closely spaced, spiral 

 threads, which in combination with the slightly weaker incremental lines 

 lend to the surface, under high magnification, a somewhat fenestrated 

 aspect. Base moderately long, marked by three tuberculated spiral cords. 

 Columella stubby, marked by nine spiral cords, which range from as 

 strong as the last basal to mere threads at the tip of the columella; aper- 

 ture irregularly pyriform, decidedly channeled anteriorly; outer lip with 

 a very deep sinus a little below the summit whose edge is reflected. Pos- 

 terior to the sinus there is a heavy hump, anterior to the sinus the outer 

 lip is protracted into a clawlike element, which is rendered sinuous by 

 the external sculpture; inner lip reflected over the columella as a very 

 heavy callus, which extends up on the parietal wall.^^g 



Dredged in four to seven fathoms off Sanibel Island, Florida, 



Found on living Atrina stranded on beach after a blow. 



Genus MANGILIA Risso, 1826 

 Maiigilia plicosasi" (C. B. Adams) PI. 38, fig. 265 



Alt., 6-8 mm., spire about half of altitude. Shell dark amber- 

 brown under dull grayish epidermis; six or seven whorls, sutures 

 distinct; 11 or 12 strong axial ribs rendered nodulous by numerous 

 revolving ridges; aperture semilunar; outer lip thickened, with pos- 

 terior varix in adult; posterior sinus shallow, rounded, subsutural; 

 interior dark; anterior canal short; no operculum. 



In shallow water. Usually on muddy and grassy bottom. 



An adult kept in plunger jar laid one egg-capsule. Others were found 

 on severed siphon of a lamellibranch which agreed with those obtained 

 from mollusc in jar and with the hatched young. 



Egg-capsules are smooth and transparent, lens-shaped, attached by 

 flat under surface; upper surface rounded, with thin central area where 

 larvae emerge. Diameter of capsule in jar 30.1 to 33 mm., height 0.32 

 mm., diam. of egg-capsule on siphon 18.5 to 31 mm., height 1.76 mm. 

 Newly laid eggs about 0.16 mm. diam. About 60 eggs in aquarium capsule, 

 less in capsule from siphon, which were further advanced. — Marie Lebour. 



339 Bartsch and Rehder: Proc. U.S. National Museum, vol. 87, No. 3070. 

 3*0 Dedicated to the naturalist G. Mangili ; Lat., plicare, to fold. 



