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; 7-12, segments of 

 mesosoma; 13-18, segments of metasoma; 19, 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; O, 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; Hf, hooks; 0, mouth. (From Sedgwick's Zoology.) 



