CAECIDAE 145 



not the common West Florida species usually called ^^spirata'" in other books. 

 See knorri and also fargoi. 



For anatomy and relationships in the worm-shells, see the excellent works 

 by J. E, Morton (1951) in the Transactions of the Royal Society of New 

 Zealand. 



Vermicularia knorri Deshayes Florida Worm-shell 



Plate 2ia 

 North Carolina to Florida and the Gulf of Mexico. 



Differing from spirata in having the early, evenly coiled part pure white 

 in color. The later whorls are very similar to spirata. Common in sponge 

 masses, and frequently washed ashore. 



Vermicularia fargoi Olsson Fargo 's Worm-shell 



Plate 2 lb 



West Coast of Florida to Texas. 



Similar to spirata and knorri, but the "turritella" or wound stage is % 

 CO I inch in length; the shell is thicker and sturdy, its color a drab grayish to 

 yellowish brown. Early whorls tan to brown, with 2 (sometimes 3) spiral 

 cords. Subsequent whorls with 3 major, brown-spotted, thick cords. Aper- 

 ture with a squarish columella corner. Minute minor threads are between 

 the main cords. Commonly found crawling on mud flats. A race occurs in 

 Texas in which the "turritella" stage is much more slender. 



Genus Tenagodus Guettard 1770 

 (Siliquaria Bruguiere 1789) 



Tenagodus squainatus Blainville Slit Worm-shell 



Plate 2ig 



Southeast Florida and the West Indies. 



A small worm-like shell with detached whorls throughout. Character- 

 ized by the long row of small holes or elongate slits on the middle of the 

 whorl. Early whorls smooth, white; later whorls becoming very spinose and 

 stained with brown. The coiling is very irregular and loose. Grows to about 

 5 or 6 inches in length. T. modestus Dall may be the young of this species. 



Family CAECIDAE 



These tiny, cucumber-shaped mollusks are occasionally found by screen- 

 ing the beach sand in warm water areas or by shaking out dead sponges. The 

 Caecums begin life in a normal snail-like manner with a tiny, spiral shell, but 

 within a few weeks they grow only in one direction to form a simple, slightly 

 curved tube. The spiral apex is usually knocked off and the hole plugged 



