237] NORTH AMERICAN MONOSTOMES 19 



The opinion expressed by Liihe (1901) that he believes Festucaria ana- 

 tis to be an echinostome, is indeed not a new view for in fact it is suggested 

 in the description of Goeze when he describes the orifice as having above it 

 a sort of a mouth. As was mentioned earlier in this work Goeze probably 

 erroneously described the crown or ring of spines for the mouth. Also 

 his description of the worms in situ in the intestine of a domestic duck 

 suggests the probability of an echinostome. Zeder (1800) evidently 

 recognized the distome nature of these worms for he described in his 

 group Echinis under the name Distoma anatis worms which he terms 

 identical with Cucullanus conoideus Bloch (1782), Planaria enten sp. 

 Goeze (1782), Festucaria anatis Schrank (1788) and Fasciola anatis Gme- 

 lin (1790). Characteristic points of his description are the large aceta- 

 bulum and the ring-like swelling around the head armed with spines. 

 In 1803 this worm was described by the same author as Distoma echinatum. 

 Rudolphi (1809) described Cucullanus conoideus Bloch, Planaria (teres 

 poro simplici) Goeze, Fasciola anatis Gmelin, Festucaria anatis Schrank, 

 Distoma anatis Zeder (1800) and Distoma echinatum Zeder (1803) as identi- 

 cal. Likewise Diesing (1850) and Baird (1853) interpret Festucaria anatis 

 as identical with Distoma echinatum. This with the opinion of Liihe 

 already given appears to be sufficient evidence to determine the probably 

 Echinostome nature of Festucaria anatis Schrank. In any event the species 

 described by Zeder (1800) as Monostoma mutabile which we now know as 

 Cyclocoelum mutabile is quite strikingly different anatomically and hence 

 clearly not closely related to Festucaria anatis based on the opinions of Zeder 

 (1800, 1803), Rudolphi (1809, 1819), and Liihe (1901). From a study of 

 the literature the writer is in agreement with the opinion of Liihe, Rudolphi 

 and Zeder that Festucaria anatis is probably Echinostomum echinatum 

 Rud. (1809). Whether these authors studied the same material can be 

 only a matter of conjecture. 



An additional fact, however, is furnished by our present knowledge of 

 the normal habitat of these worms which with few exceptions are confined 

 to partially closed cavities of the body, the infraorbital sinus, and areal 

 sacs for Cyclocoelum and Hyptiasmus, and the trachea for Typhlocoelum. 

 As has been previously noted the habitat of Festucaria anatis is the intes- 

 tine of a domestic duck. 



The genus Cyclocoelum Brandes (1892) was formulated to include the 

 following species Monostoma mutabile, M. flavum, M. arcuatum, M. 

 tringae, and M. ellipticum with the following description: first four species 

 collected from the body cavity and infraorbital sinus of water birds the 

 fifth Monostoma ellipticum, from the lungs of Rana maculata, with intes- 

 tinal crura anastomosing in the posterior end. 



In the acceptance of the genus name Cyclocoelum Brandes (1892) the 

 writer realizes that he is subject to criticism on account of the genus 



