164 Marine Shells of the Western Coast of Florida 



with light color, epidermis brownish; old living shells usually without 

 color, worn and covered with a growth of marine algae. Albino speci- 

 mens are not uncommon. Spire short, body whorl large, shoulder 

 of whorls tuberculate or smooth; sutures distinct, slightly channeled; 

 revolving sculpture of coarse threads; aperture large, widely open, 

 prolonged into a long, straight, open canal; columella a little sinuous, 

 outer lip sharp, Urate within; operculum ovate. 



Deformities of shells of B. " contrarium' are more frequently 

 encountered than in the shells of any other species of gasteropod 

 found in this region. The most common abnormalities involve the 

 long canal, which may be contorted and bent in almost any direc- 

 tion and at any angle. Occasional specimens show partial or com- 

 plete duplication of the canal. 



Perry has observed a few embryonic shells from fresh egg rib- 

 bons which show abnormalities of development similar to those 

 seen in some adult shells of SO to 100 millimeters height. 



An aberrant form of B. " contrariuvv" , Plate 34, figures 233 b, c, 

 is found in a fairly circumscribed area of the Gulf of Mexico toward 

 the eastern end of Sanibel Island. Shells and living mollusks of 

 this form have not been found elsewhere in the vicinity. The shells 

 approach the type of B. perversum (Linne). They are thicker, 

 heavier, more solid, the shoulder wider and more sloping, the peri- 

 pheral tubercles stronger and more widely spaced, the spire flatter, 

 aperture wider and canal much shorter than in the common B. 

 ^'contrarium'. The columella is thick, with a tumefaction at the 

 site of the columellar thickening of B. perversum, Plate 34, figures 

 233, D. E. The prominent characters of this shell are the squat 

 outline — a reversed pyramid; its weight and solidity; the decidedly 

 great proportion of shoulder breadth to the total height and the 

 thick, swollen columella. 



Egg capsules of Busycon "contrarium (Conrad)" PL 51, figs. 349a, b, c 

 Busycon "contrarium/' produces long twisted ribbons of from 

 30 cm. to more than a meter in length, closely set along one side with 

 disc-shaped capsules 30 mm. in diameter. The capsules are four to five 

 mm. thick and have free ruffled margins on each flat side. Busycon 



