546 FRESH-WATER BIOLOGY 



5(8) Terminal hooks over 90 /* long. Embryos under 50 /z long 6 



6 (7) Body 8 to 32 mm. long. 



Embryos very small. 



Neoechinorhynchus emydis (Leidy) 1852. 



FIG. 846. Neoechinorhynchus emydis. Proboscis, 



Body much elongated, cylindrical. Female 

 10 to 32 mm. long, 0.7 mm. in maximum 

 width. Male 8 to n mm. long by 0.7 mm. 

 broad. Proboscis globose, 0.175 nun. long. 

 Hooks large, in anterior row strongly recurved, 

 95 to 103 /x long, in middle row 49 to 59 n 

 long, in basal row 35 to 54 /x long, nearly 

 straight. Embryos very small, oval, 16 by 



Originally described by Leidy from the in- 

 testine of various species of Emys from 

 Pennsylvania and Maryland. Frequent in 

 Malacoclemmys geographicus (Lesueur) and 



Cleave.) 



and embryos, X 230. (After Van p^ '" g< ^ ^ax ^om the Illinois 



River. 



(6) Body 2 to 13 mm. long. Embryos about 40 M long. 



Neoechinorhynchus tenellus (Van Cleave) 1913. 



FIG. 847. Neoechinorhynchus tenellus. 



Body small, both ends curved strongly ventrad. 

 Posterior two-thirds of body markedly attenuated. 

 Female 3.5 to 13 mm. long, 0.6 mm. in maximum 

 breadth; males 2 to 8 mm. long, 0.5 mm. broad. Pro- 

 boscis nearly cylindrical, 0.150 mm. long by 0.135 nun. 

 wide. Anterior hooks 90 to iio;u long, heavy; middle 

 hooks 38 AI long; basal hooks 27 fj. long. Embryos 

 37 to 45 by 12 to 16 /* 



Intestine of Esox lucius L. from Lake Marquette 



Proboscis, X 75; hooks and 

 X 230. (After Van Cleave.) 



embryo,' near Bemidji, Minnesota. 



8 (5) Terminal hooks usually less than 90 n long. Embryos over 50 n long. 



Neoechinorhynchus cylindratus (Van Cleave) 1913. 



Large, straight-bodied. Female 10 to 15 mm. 

 long, 0.7 mm. in maximum width, just behind 

 proboscis. Male 4.5 to 8.5 mm. long, 0.5 to 0.7 

 mm. in maximum breadth near anterior end. 

 Proboscis slightly broader (0.172 mm.) than 

 long (0.15 mm.). Anterior hooks 79 to 97 n 

 long, heavy, strongly recurved, center hooks 

 37 At long, basal hooks 21 to 25 n long. Em- 

 bryos 49 to 51 n long by 15 to 21 fj. broad. 



In intestine of Micropterus sdamoides (La- 

 ce"p.). Pelican Lake, Minnesota, and of An- 

 gutila chrysypa, Woods Hole, Massachusetts. 



FIG. 848. 

 boscis, X 75: 

 Van Cleave.) 



Neoechinorhynchus cylindratus. Pro- 

 hooks and embryos, X 230. (After 



