338 Dr. O'Bryen Bellingham on Irish Entozoa. 



Genus 11. Amphistoma. 



(Derived from a/x^i, utrinque, and rjTOfxa, os.J 



Body soft and cylindrical. Two pores, one anterior, the other pos- 

 terior. No abdominal pore. 



The genus Amphistoma was established by Abildgaard under 

 the name Strigea, because the animal serving as the type had 

 been discovered in the owl. Rudolphi gave it the name which it 

 at present bears. 



The species are not numerous; Rudolphi enumerates but 

 twenty-one, of which three are doubtful. They are most common 

 in birds ; a few occur in mammalia and reptiles. They inhabit 

 generally the alimentary canal. 



They have been arranged by Rudolphi in two sections, accord- 

 ing as the head is distinct or continuous. The species in this list 

 (which have been determined) belong all to the first section. 



Capita discrete . 



. „ ^ f Small intestine of herring-gull (La- 

 1 . Amphistoma longicolle * . . | ^^^ argentatus). 



pSmall intestine of moor-buzzard (5m- 

 i T , j teo rufus). 

 2- macrocephalumf^ g^^j^ intestine of peregrine falcon 



[_ (Falco peregrinus). 



from the body, and has a triangular shape (hence its name). The 

 pore is orbicular, rather inferior than anterior, when the animal has 

 been kept in spirits for some time. The body is somewhat broader 

 posteriorly than anteriorly, convex upon the dorsal, concave upon 

 the abdominal surface ; the posterior extremity is distinctly notched. 

 * The Amphistoma loiigicoUe was so named from the length of the 

 neck ; it occurs only in birds of the gull or heron tribe. It is about 

 half an inch in length, cylindrical, and of a reddish brown colour. 

 The head is distinct, of a subcordate shape, broadest where it joins 

 the neck ; the neck is wrinkled transversely, and increases in thick- 

 ness until it meets the body ; the latter is shorter than the neck and 

 smooth. This species is well figured in Bremser's folio work. 



t The Amphistoma macrocephalum, from the small intestine of the 

 moor-buzzard (Buteo rufus), is a minute species, the longest speci- 

 men measuring only a line and three-quarters ; colour yellowish 

 white; head thicker but shorter than the body, from which it is 

 separated by a narrow fissure, as if a string had been tied round it ; 

 body subcylindrical, incurved ; anterior pore irregularly lobed ; lobes 

 apparently four or five ; posterior pore small and orbicular ; margin 

 sometimes crenate ; in a few specimens a small cylindrical body pro- 

 jected slightly from it. 



