PARASITIC ROUNDWORMS 



551 



35 (34) Proboscis with sixteen longitudinal rows of hooks. 



Arhythmorhynchus pumilirostris Van Cleave 1916 



Female up to 30 mm. long, and 1.5 mm. broad. Proboscis 0.45 

 mm. long, 0.114 mm. wide at base, 0.095 mm. at tip, 0.18 mm at 

 center. Embryos 65 to 89 /* long, 18 /x broad. Middle shell with 

 evagination at each pole. 



Yrova. hiti^xn {Botaiiruslentiginosus); Washington D. C. 



Fig. 855. 



Arhythmorhynchus pumilirostris. r ofile, anterior end 

 body. X 95- (After Van : leave.) 



36 (11) In anterior region of mat'\e specimens prominent bulbous enlarge- 

 ment, separated Irom body by slender cyHndrical neck. 37 



The bulb is embedded in the intestinal wall or may even be in the body cavity when the 

 slender region traverses the wall connecting with the body of the parasite in the intestine. In 

 handling such material the proboscis may easily be partly or completely torn ofiF, and the para- 

 site is then difficult to identify as the characteristic bulb at least is gone. 



37 (38) Bulb consists of the proboscis, 

 bulb in radial lines. 



Hooks on the anterior face of the 

 (Females of) FilicoUis Liihe 191 1. 



Representative North American species. 



FilicoUis hotidus Van Cleave 1916. 



In females thus far reported under this name for North America the bulb is wanting; it may 

 be present in older specimens and in fact is described in specimens recorded under the name 

 E. anatis which may belong here. 



Compare number 22 in key. 



38 (37) Bulb consists of anterior part of neck only. Proboscis extends an- 

 teriad from bulb. . . . Pomphorhynchus MonticelH 1905, 



Proboscis long, cylindrical, with many hooks. Neck very long, expanded in anterior region, 

 slender, cyHndrical in posterior portion. In intestine of fishes; one of the commonest types 

 in European fresh-water hosts. Not infrequent in North American fresh-water fishes; species 

 not described. 



IMPORTANT REFERENCES ON NORTH AMERICAN PARASITIC 



ROUNDWORMS 



GENERAL WORKS 



See also list in Chapter XIII, page 452 

 1 89 1. Die Nemathekninthen. Heft i, 120 pp, 



Hamann, 



Heft 2, 120 pp., II pi. Jena. 

 Leuckart, R. 1876. Die menschliche Parasiten. 

 Acanthocephala]. 882 pp., 401 figs. Leipzig. 



Vol. 



, 10 pi. 1S05. 

 2 [Nematoda, 



