INVERTEBRATE EUCOELOMATES 



265 



like structures; if solitary forms or colonies are 

 stalked, individuals usually are opaque, tough, and 

 club-like {called sea clubs); if not stalked, individuals 

 usually are semitransparent, fragile-appearing, and 

 sac -like (called sea squirts); sea clubs and sea squirts 

 frequently and abruptly eject water when disturbed; 

 ascidians are hermaphroditic filter feeders; colonial 

 and compound forms result from asexual budding; in- 

 habit shallow water in rocky tide pools to deeps. 



Subphylum CEPHALOCHORDATA (Lancets) 



Diagnosis: mostly 5 inch to 4 inches long, slender, 

 simple structured and finless, but fish-like; adult with 

 all chordate characters; gills generally involved in 

 filter feeding; sexes separate, reproduction strictly 

 sexual; shallow water, marine sand dwellers, but 

 some are intertidal, at low tide, lancets may jump 



out and back into sand when disturbed (Figure 

 15.11). 



SELECTED READINGS* 



Bather, F. A., 1900. The Echinoderms. In A Treatise on 



■Zoology (R. Lankester, ed.) Vol. 3, A & C Black, 



London. 

 Clark, A. H., 1915-1950. A Monograph of the Existing 



Cnnoids. Bull. 82, U. S. Nat. Mus., Washington, D. C. 

 Fisher, W. K., 1911-1930. Asteroidea of the Xorth Pacific and 



Adjacent Waters. Part 1: Phanerozonia and Spinulosa 



(1911). Parts 2 and 3: Eorcipulata (1928 and 1930). 



Bull. 76(1-3), U. S. Nat. Mus., Washington, D. C. 

 Hyman, L. H., 1955. The Invertebrates. Vol. 4; Echino- 



dermata. McGraw-Hill Book Co., New York. 

 . 1959. The Invertebrates. Vol. 5: Smaller Coelomate 



Groups. McGraw-Hill Book Co., New York. 



*See also p. 212. 



