DISTOMA ORASSUM. 



193 



D. Busldi, Lankester. 

 Dicrocoelium Busldi, Weinland. 



General and Specific Characters. — A trematode helminth varying from an inch and 

 a half to thi-ee inches in length, and having an average breadth of | of an inch; 

 especially also characterized by its uniform and considerable thickness, combined with 

 the presence of a" double alimentary canal which is not branched;" the body is pointed 

 in front, and obtusely rounded posteriorly ; the integument being smooth and unarmed ; 

 the reproductive orifices placed immediately above the ventral sucker : the testes 

 form two bulky, lobed organs, situated below the ventral acetabulum, and disposed in 

 the middle line, one in front of the other ; the uterine folds occupy only the front part of 

 the body, the margins of which also display two viteUigene glands, one on either side of 

 the intestinal' tube ; the excretory organ consists of a central trunk with diverging 

 branches. 



This is a good species, and appropriately named ; for, althougli 

 Yon Siebold (in Miiller's " ArcHv" for 1836, p. 234, and in his 

 " Lehrbuch," vol. i. p. 143) refers to a Distome infesting Hirundo 

 urhica under this title, he has given no description of the worm. 

 Diesing places Von Siebold' s 2). crassum among his species inqui- 



I'lG. 42.— Outline drawing oi Distoma crassnm. Busk ; the parts not actually visible, in the speci- 

 mens examined, being indicated by dotted lines; «, oral sucker; J, acetabulum ; o, reproduc- 

 tive papilla ; d, uterine canal ; e, ovary ; /,/, testes ; g, g, g, g, intestinal tubes ; h, aquiferous 

 or excretory canal. — Original. 



rendfp,, and it is very probably identical with the D. maculosum of 

 Rudolphi. No other instance has occurred since the original fourteen 



c 



