COLLEGE ZOOLOGY 



Order 10. Eurypterida (Fig. 328). - - The EURYPTERIDA 

 lived in both salt water and fresh water during the Silurian and 

 Devonian periods (Table XVII), and are known to us only as 

 fossils. They appear to represent a condition intermediate be- 

 tween Limulus and the SCORPIONIDEA. 



FIG. 328. FIG. 330. FIG. 331. 



FIG. 328. Order EURYPTERIDA. Eurypterus fischeri, dorsal surface. 

 a, ocellus; b, lateral eye; 2-6, appendages of prosoma; 7-72, segments of 

 mesosoma; 13-18, segments of metasoma; IQ, tail spine. (From the Cam- 

 bridge Natural History, after Holm.) 



FIG. 329. PYCNOGONIDA. Ammothea pycnogonoides. (From Sedgwick's 

 Zoology, after regne animal.) 



FIG. 330. - - TARDIGRADA. Macrobiotus schultzei. Md, stomach; 0, mouth; 

 Ov, ovary; Spd, salivary glands; T, malpighian tubules; Vm, pharynx ; Vs, 

 accessory gland. (From Sedgwick's Zoology, after Greeff.) 



FIG. 331. PENTASTOMIDA. Pentastomum tanioides. A, anus; D, intes- 

 tine; ///, hooks; O, mouth. (From Sedgwick's Zoology.) 



