612 W. S. NICKERSON, 



vious classifications. I agree fully with Jägerskiöld ('99) that it is 

 too early to give a fiual revision of the family Aspidobothridae. That 

 can be done only when more forms shall have becorae knowu and 

 the life histories more fully worked out. It is possible as he has 

 suggested that the present somewhat isolated position of the family 

 may have be exchanged for one indicating a closer relationship to the 

 digenetic forms. 



I have made no attempt to give the synonymy nor to furnish 

 complete lists of the literature since these are already available in 

 the propers of Monticelli and Braun up to the time of their publi- 

 cation. The Hterature lists which I give are intended to include only 

 the propers containing original descriptions and publications which 

 have appeared since the preparation of the bibliography given by 

 Braun ('89 -'93). 



The genera which I recognize as comprising the family Aspido- 

 hothridae are the following: 



Aspidogaster von Baer (1827) 



Cotylaspis Leidy (1857) 



Macraspis Olsson (1869) 



Stichocotyle Cunningham (1884) 



Cotylogaster Monticelli (1892) 



I recognize five genera as did Monticelli tho' but three of 

 these, Aspidogaster, Macraspis, and Cotylogaster are the same as 

 given by him. Moreover it has been necessary to make greater or 

 less change in the definition of each of these genera. The genus 

 Aspidogaster remains essentially unchanged except that the form which 

 Leidy described as Cotylaspis insignis and which Monticelli in- 

 cluded in the genus Aspidogaster has been taken out and restored to 

 its Position as the type of a distinct genus, Cotylaspis, a position to 

 which the work of Osborn ('98) and Kofoid ('99) has shown it to 

 be entitled. Some ehanges have been made in the definition of the 

 genus Macraspis as the recent work of Jägerskiöld ( '99) has made 

 necessary. The genus Cotylogaster has also been sliglitly modified to 

 include the uew form C. occidentalis. These chauges do not however 

 essentially modify the defiuitions of these three genera as given in 

 Monticelli's Classification. 



The genus Aspidocotyle Dies. I have excluded from the family 

 following in so doing the example of Braun (89—93, p. 907) who has 

 placed it among tlie Amphistomidae. So long as nothing more is known 



