CERITHIIDAE 15 3 



2 yellowish white, swollen varices on the spire. A very common species 

 found in large colonies on mud flats. 



Cerilhidea 



Balillar'ia 



Cerilhium 



Figure 39. Last whorl and opercula in the Horn Shells. (From J. Bequaert in 



Johusoina.) 



Subfamily BATILLARIINAE 

 Genus Batillaria Benson 1842 



Cerithium-like in appearance. Siphonal canal very short and twisted to 

 the left. Outer lip smooth inside. Operculum round, multispiral and horny, 

 while in Cerithidea and Cerithium it is paucispiral. 



Batillaria mi7iima Gmelin 



South half of Florida and the West Indies. 



False Cerith 



Plate 19s 



V2 to % inch in length, resembling the Dwarf Cerith, C. variabile (see 

 below). Color varies from black, gray to whitish, and often has black or 

 white spiral lines. Finely nodulose with coarse axial swellings and uneven 

 spiral threads. The siphonal canal is very short and twisted slightly to the 

 left. Operculum multispiral. A very common intertidal species. Percy 

 Morris (i95i» pl- 31^ %• 15) labels this species as Cerithidea turrita. 



Family CERITHIIDAE 

 Genus Cerithium Bruguiere 1789 



Thericium Monterosato is this genus. The operculum is horny, thin, 

 brown and paucispiral. Most species in the genus are shallow-water dwellers. 



Cerithium floridanum Morch 



North Carolina to the south half of Florida. 



Florida Cerith 



Plate 1911 



I to 1V2 inches in length, elongate. Spire pointed, with 2 or 3 white, 

 former varices on each whorl. Siphonal canal well-developed. With several 

 spiral rows of 18 to 20 neat beads per whorl between which are fine, granu- 

 lated spiral threads. Color whitish with mottlings and specklings of reddish 

 brown. Distinguished from C. literatimi by its more elongate shape and 

 neater, smaller, more numerous beads. Common in shallow water. 



