INVERTEBRATE TYPES 



1, Hydra; 2, earthworm; 3, a trochophore larva; 4, a rotifer; 5, Ba- 

 lanoglossus ; 6, Trochosphara ; 7, Amphioxus ; 8, a tunicate ; 9, Bonellia ; 

 10, a fresh water annelid reproducing by fission. Fig. 3, from Korschelt 

 and Heider after Hatschek; 4, from K. & H. after A. Agassiz; 6, from 

 K. & H. after Semper; 9, from Doncaster; the others are original, 9 

 from a preparation by Powers. Fig. 1, i, intestine; m, mouth; t, ten- 

 tacles. Fig. 2, c, crop ; ce, cffilome ; g, gizzard ; i, intestine ; m, mouth ; 

 n, nerve cord; np, nephridium (kidney) ; sv, seminal vesicles; sr, seminal 

 receptacles; ph, pharynx. Figs. 3 & 4, a, anus; cv, contractile vesicle or 

 bladder; e, excretory duct; i, intestine; m, mouth; mx, mastax (grind- 

 ing pharynx) ; pr, pre-oral, and po, post-oral ciliated rings; pg, pharyn- 

 geal glands; s, stomach; o, ovary. Fig. 6, c, cloaca; e, excretory duct; 

 m, mouth; mu, muscle; pr, pre-oral, and po, post-oral ciliated rings; 

 o, ovary; pg, pharyngeal gland. 



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