341] NORTH AMERICAN PARAMPHISTOMIDAE—STUNKARD 61 



I have been unable to find any record of work done on the param- 

 phistomes of fish between that of Diesing (1836) and MacCallum (1905). 

 Daday (1907) described two species of Diplodiscus, two species of a new 

 genus he called Microrchis, three species of a new genus named Pseudo- 

 cladorchis, and added Amphistoma oxycephalus Dies, with two new 

 species to the genus Chiorchis. He included a section on the anatomy 

 and histology of the forms. 



The only paramphistomes from amphibians are four species of Dip- 

 lodiscus reported from frogs : D. subclavatus from the frogs of Europe, 

 D. temperatus from those of North America, and D. megalochnis and 

 D. microchrus from Australian frogs. 



Information concerning paramphistomes of reptiles is very scanty. 

 Braun (1901) lists three species from turtles: Amphistoma grande Dies- 

 ing, A. scleroporum Creplin, and A. sp. Bellingham. Bellingham (1844) 

 listed Amphistoma sp. from the intestine of Chelonia imbricata but gives 

 no description, so this species should receive no further consideration. 

 Braun (1901) supplemented the description of Creplin (1844) by a brief 

 report of the single specimen of A. scleroporum from the museum at 

 Greifswald, but the worm was sexually immature and consequently 

 the observations were limited. A. grande was collected by Natterer 

 from the intestine of five species of turtles in Brazil, but the descrip- 

 tion of Diesing is confined to the external appearance and the material 

 may have comprised more than one species. One other species is known 

 from turtles, a form described by Looss (1902) as A. spinulosum from 

 the intestine of Chelone mydas. The description of Looss is very com- 

 plete but because of the scarcity of known species and our limited knowl- 

 edge of the group, at that time he refrained from any attempt at classi- 

 fication. He stated that the species is probably closely related to A. 

 scleroporum and A. grande. 



In addition to the description of the species, Looss (1902) discussed 

 the question of the oral sucker and the pharynx in the group and com- 

 piling evidence from comparative anatomy and embryology, he argued 

 that the anterior sucker of the amphistomes should be regarded as homolo- 

 gus to the oral sucker of the distomes. In this paper also he described 

 the muscular thickening at the caudal end of the esophagus as a pharynx 

 and described a peristaltic contraction of the organ from the anterior 

 to the posterior end, altho in an earlier paper (1896) he had stated that 

 the esophageal thickening of Gastrodiscus was not a true muscular 

 pharynx. Concerning this latter structure, Odhner (1911) says, "Ich 

 verwende diese Bezeichnung, weil es mir doch nicht so ganz sicher 

 erscheint, dass es sieh hier um ein dem gewohnlichen Distomenpharynx 

 homologes Organ handelt. Auch wenn es so ware, konnte iibrigens der 



