302 



COLLEGE ZOOLOGY 



marine; head large; eyes large and 

 often complex (Fig. 184); radula 

 present; the foot is modified into 8 

 or 10 prehensile arms in the octopuses 

 and squids, but many tentacles in 

 the nautili; muscular funnel (si- 

 phon); shell external, internal, or 

 none; and dioecious. 

 Order 1. Tetrabranchia. Calcareous shell, 

 closely coiled, tentacles numer- 

 ous and without suckers; eyes 

 without lens; no chromato- 

 phores; no ink sac; two pairs 

 of gills and two pairs of ne- 

 phridia. Ex. Nautilus pompilius, 

 the pearly or chambered nau- 

 tilus (Fig. 185). 

 Order 2. Dibranchia. Shell absent or re- 

 duced, and internal, calcareous, 

 or horny, not coiled; body cylin- 

 drical or globose; one pair of 

 gills, one pair of ncphridia; 

 tentacles 8 to 10, with suckers 

 or hooks; eyes with lens; chro- 

 matophores and ink sac present. 

 Ex. Loligo pealii, squid (Fig. 

 183). 



SELECTED COLLATERAL 

 READINGS 



Abbott, R.T., American Sea Shells. Van Nos- 

 strand. New York, 1954. 



Clench, W.}., Turner, R.D., et al. Johnsonia 

 Monographs of the Marine Mollusks of the 

 Western Atlantic, 1941 to date. Department 

 of Mollusks, M.C.Z., Harvard Univ., Cam- 

 bridge. 



Coker, R.T., and Clark, A.F. "Natural History 

 and Propagation of Fresh Water Mussels." 

 Bull. U.S. Bur. Fisheries, 37:77-181,. 

 1921. 



Grave, B.H. "Natural History of the Ship- 

 worm, Teredo navalis, at Woods Hole, 

 Mass." Biol. Bull, 55:260-282, 1928. 



MacGinitie, G.E., and MacGinitie, N. Natural 

 History of Marine Animals. McGraw-Hill, 

 New York, 1949. 



Pilsbry, Henry A. "Land Mollusca of North 

 America (North of Mexico)." Acad. Nat. 

 Sci. Phila. Monograph 3, Vol. 1, Parts 1 and 

 and 2, 1939 and 1940; Vol. 2, Parts 1 and 2, 

 1946 and 1948. 



Pratt, H.S. A Manual of the Common Inverte- 

 brate Animals. Blakiston, Philadelphia, 

 1932. 



Prosser, C.L., et al. Comparative Animal 

 Physiology. Saunders, Philadelphia, 1950. 



Robson, G.C. A Monograph of the Recent 

 Cephalopoda. British Museum, London, 

 1932. 



Shrock, R.R., and Twenhofel, W.H. Principles 

 of Invertebrate Paleontology. McGraw-Hill, 

 New York, 1953. 



Stiles, Karl A., and Stiles, Nettie R. "The 

 Pearl, A Biological Gem." Bios, 14:3-16, 

 1943. 



