546 FRESH-WATER BIOLOGY 



S (8) Terminal hooks over 90 11 long. Embryos under 50 /i long 6 



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



Neoechinorhynchus emydis (Leidy) 1852. 



Fig. 846. Neoechinorhynchus emydis. Proboscis, 

 X 75; hooks and embryos, X 230. (After Van 

 Cleave.) 



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 li long, in middle row 49 to 59 li 

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

 straight. Embryos very small, oval, 16 by 



11 M. 



Originally described by Leidy from the in- 

 testine of various species of Emys from 

 Pennsylvania and Maryland. Frequent in 

 Malacoclemmys geographicus (Lesueur) and 

 Pseudemys elegans Max from the Illinois 

 River. 



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



Neoechinorhynchus tenellus (Van Cleave) 1913. 



Fig. 847. Neoechinorhynchus tenellus. 

 Proboscis, X 7%; hoolts and embryo, 

 X 230. (After Van Cleave.) 



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 maximtim 

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

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

 wide. Anterior hooks 90 to no /i long, heavy; middle 

 hooks 38 11 long; basal hooks 27 ix. long. Embryos 

 37 to 45 by 12 to 16 )Li. 



Intestine of Esox lucius L. from Lake Marquette 

 near Bemidji, Minnesota. 



8 (5) Terminal hooks usually less than 90 m long. Embryos over 50 m 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 (o.is mm.). Anterior hooks 79 to 97 /i 

 long, heavy, strongly recurved, center hooks 

 37 M long, basal hooks 21 to 25 ;u long. Em- 

 bryos 49 tosin long by 15 to 21 M broad. 



In intestine of Micropterus salamoides (La- 

 c6p.). Pelican Lake, Minnesota, and of An- 

 guUla ckrysypa, Woods Hole, Massachusetts. 



