343] NORTH AMERICAN PARAMPHISTOMIDAE—STUNKARD 63 



tere dieser Gattung oder der Unterfamilie, zu der sie sich friiher oder 

 spater auswachsen wird, betrachtet ich den Aul'bau der Excretionblase 

 aus zwei sehr langen, bis ins Kopfende einfachen, unter sich nicht ver- 

 bundenen Sehenkeln und den Aufbau des Lymphgefasssystenies aus 

 jederseits drei in der Umgebung der Saugnapfe verastelten Schlauchen." 



He might well have added to his list of differences that in 8. spinu- 

 losum there is a single loop of the excretory vesicle wound dorsally 

 over the cecum of each side while in S. sclcroporum there are eight loops 

 winding irregularly around the cecum of each side. In the same article 

 (p. 355) speaking of the excretory system in paramphistomes of mammals 

 he says this system is situated deep in the body and in the larger groups 

 is a stable and conservative organsystem. In a former paper Looss 

 (1902 :837) says, "Zwischen der Species einer natiirlichen Gattung 

 bestehen anatomische Unterschiede nicht; die Speciescharaktere werden 

 dargestellt allein durch Differenzen in der Grosse des Korpers und der 

 einzelnen Organe, Hand in Hand mit denen leichte Veranderungen ihrer 

 Form, ihrer Lage und wenn sie reicher gegliedert oder in eine Anzahl 

 von Theilstucken zerfallen sind, Aenderungen in der Zahl der Glieder 

 resp. der Theilstiicke gehen konnen." As a matter of fact, the argument 

 of Looss in my opinion appears to show clearly that S. scleroporum and 

 S. spinulosum are not members of the same genus ; as indeed he has al- 

 ready suggested himself that in future researches a new genus will have 

 to be created to contain S. spinulosum. 



The single paramphistome reported from snakes was described by 

 Cohn (1903) as Amphistomum dolichocotyle, and in his (1904) classifi- 

 cation of the Diplodiscinae placed in the genus Catadiscus. It is from 

 the intestine of Herpetodryas fuscus. 



The only paramphistomes previously known from North America 

 are Amphistoma grande, reported by Leidy (1888) from the intestine of 

 the terrapin ; two specimens from the small intestine of the muskrat 

 which according to the same author, "appear to belong to Amphistoma 

 subtriquetrum" ; Diplodiscus temperatus Stafford long considered iden- 

 tical with D. subclavatus Dies. ; and Wardius zibethicus Barker and 

 East, from the cecum of Fiber zibethicus. The reports of Leidy contain 

 no description except the length of the worms. Barker and East suspect 

 that Leidy 's specimens from the muskrat belong to their new genus and 

 species Wardius zibethicus ; and it is not unlikely that the specimens from 

 the terrapin are specificallj'- identical with those described here as Alasso- 

 stoma magnum Stunkard 1916. Neither the description of Stafford 

 nor that of Barker and East contains complete anatomical information. 

 Stafford distinguished between the lymph and excretory systems. 

 Barker and East make no mention of the lymph system ; they 



