46 



ZOOLOGY. 



is sold for soups in Chinese markets. Our native com- 

 monest species is Pentada frondosa (Fig. 48). 



Fig. 48. — Common Sea-cucumber, with the gills nearly expanded. 



erton. 



After Em 



Literature. 



O. J. Romanes. ,Tell} r -fish, Starfish, and Sea-urchins, 1885. 



J. Midler. Seven Memoirs on the Larvae and Development of 

 Echinoderms. Berlin, 1846-54. 



A. Agassiz. Embryology of the Star-fish, 1864. 



E. Metschnikoff. Studien liber die Entwickelungsgeschichte der 

 Echinodermen und Nemertinen. St. Petersburg, 1869. 



H. Ludwig. Morphologische Studien an Echinodermen. Leip- 

 zig, 1877-79. 



