546 FRESH-WATER BIOLOGY 



5 (8) Terminal hooks over go (x long. Embryos under 50 ju long 6 



6 (7) Body 8 to 32 mm. long. Embryos very small. 



N eoechinorhynchiis emydis (Leidy) 1852. 



Fig. 846. Neoechinorhynchus emydis. 

 X 75; hooks and embryos, X 230. 

 Cleave.) 



Proboscis, 

 (After Van 



Body much elongated, cylindrical. Female 



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

 width. Male 8 to 11 mm. long by 0.7 mm. 

 broad. Proboscis globose, 0.175 mm. long. 

 Hooks large, in anterior row strongly recurved, 

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

 long, in basal row 35 to 54 11 long, nearly 

 straight. Embryos very small, oval, 16 by 



11 fX. 



Originally described by Leidy from the in- 

 testine of various species of Emys from 

 Pennsylvania and Maryland. Frequent in 

 M alacoclemmys geographicus (Lesueur) and 

 Pseudemys elegans Max from the lUinois 

 River. 



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



Neoechinorhynchus tenellus (Van Cleave) 1913. 



Neoechinorhynchus tenellus. 

 75; hooks and embrj-o, 



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 vara. 

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

 hooks 38 /i long; basal hooks 27 /x long. Embryos 

 37 to 45 by 12 to 16 M- 



Intestine of Esox lucius L. from Lake Marquette 

 near Bemidji, Minnesota. 



X 230. (After Van Cleave.) 



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



Neoechinorhynchus cylindratus (Van Cleave) 19 13. 



Fig. 848. 

 X75 

 Van Cleave.) 



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 ^ 

 long, heavy, strongly recurved, center hooks 

 37 /x long, basal hooks 21 to 25 /x long. Em- 

 bryos 49 to 51 )U long by 15 to 21 fx broad. 



In intestine of Micropterus salamoides (La- 

 cep.). Pelican Lake, Minnesota, and of An- 

 guilla chrysypa, Woods Hole, Massachusetts. 



