496 THE ANATOMY OF INVERTEBRATED ANIMALS. 



pores on the genital plates, through which their products are 

 extruded. Hoffmann has fcund the peritoneal fluid of the 

 males full of spermatozoa. 



FIG. 145. Development of an Echinid. (After Mflller.) A, Echinopsedinm of KcM- 

 mts pulchettus in the gastrula stage. B, fully-developed Echinopsedium (Pluteus) 

 of the same species: a, mouth; &,~?tomach and intestine; c. anus; AF, processes 

 of the body into which prolongations of the internal skeleton extend. C, the 

 Echinopaedium of an Echinid in which the Echinoderm is so far advanced that 

 the spines, pedicels, and pedicellariae are visible. D, Echinopaedium of Echinus 

 lividus: a, mouth; a', gullet; J, stomach; V, intestine; c, rudimentary Ecliino- 

 derm; c', the anibulacral sac; c", the external opening of its duct; A A, F F, S, 

 the processes of the body. 



In the JEehinicka, as in the Ophiuridea, the Echinopae- 



