14 ILLINOIS BIOLOGICAL MONOGRAPHS [232 



DESCRIPTION OF FAMILIES 



Validity of the older name. — The question raised by Liihe (1901) 

 regarding the use by Looss (1899) of the family name Monostomidae 

 Cobbold 1866 [erroneously credited to Monticelli by Liihe (1901) and by 

 Stossich (1902)] without a type genus Monostomum and the extended 

 discussion of Looss (1902) is a needless one if the rules of the International 

 Code be applied. Article V of this code deals specifically with the family 

 name which by the acceptance of the genus name Cyclocoelum becomes 

 Cyclocoelidae. 



CYCLOCOELIDAE Kossack 1911 



Diagnosis. — Endoparasitic trematodes of large to middle sized muscu- 

 lar bodies. Mouth opening terminal or subterminal surrounded by 

 muscular sucker usually much reduced. Ventral acetabulum sometimes 

 present, pharynx large, muscular; esophagus long. Intestinal crura 

 simple or possessing internal ceca, anastomosing in the posterior end of 

 the body. Excretory bladder between posterior intestinal arch and end 

 of body with median dor so- terminal pore. Genital pore median, usually 

 ventral to pharynx. Copulation organs present, well developed; seminal 

 vesicle in cirrus pouch. Vitellaria in general lying between body wall and 

 intestinal crura, sometimes surrounding the latter. Genital glands between 

 intestinal crura, simple or lobed, forming the points of a triangle. Laurer's 

 canal wanting; receptaculum seminis present. Uterus strongly developed 

 lying in more or less regular folds between intestinal crura over which they 

 sometimes extend, usually filling entire space between crura. Eggs numer- 

 ous, without polar filament, usually containing well developed miracidia 

 with characteristic double eye spots. 



Parasitic in body cavity, lungs and nasal cavities of water birds. 



Type and only American genus Cyclocoelum. Other genera Haemato- 

 trephus, Hyptiasmus, Typhlocoelum, Tracheophilus, Ophthalmophagus, 

 Spaniometra and Bothriogaster. 



The foregoing diagnosis differs from that of Kossack in noting that an 

 oral sucker and a receptaculum seminis have been found in two genera of 

 this family, namely Cyclocoelum and Haematotrephus. In the genus 

 Cyclocoelum these organs have been found in the species described in this 

 paper as well as in the following European species: Cyclocoelum problema- 

 ticum Stoss., Cyclocoelum ovopunctatum Stoss., Cyclocoelum brazilianum 

 Stoss., and in Cyclocoelum tringae (Brandes) as well as in Haematotrephus 

 similis Stoss. 



