Mr. H.J. Carter on Microscopic Filaridse. 103 



bay, the mucous membrane of the rectum is prolapsed as it were 

 into an expanded floral or digitated form, which is covered with 

 cilia in constant and active motion. 



Comparison of Filaria Medinensis with Urolabcs palustris. 



On comparing Filaria Medinensis with Urolabes palustris, it 

 must now be evident that they both belong to the same family, 

 if not to the same genus. 



Thus, externally the form is the same, — that is, both are 

 equal in size for a long extent, and then diminish towards the 

 extremities*. The mouth and anus are the same as regards 

 position. There are two evident papilla? on the head in each; 

 but with the mouth they do not bear the same proportion to 

 the body in both, for reasons which will be more evident by-and- 

 by. There is no vaginal orifice or vulva in Filaria Medinensis, 

 while there is one in Urolabes. Lastly, the tail is curled up and 

 abortive, compared with the development of the body in the 

 adult of F. Medinensis, — though the opposite is the case with its 

 young one, where it is more like that of Urolabes palustris, and 

 especially that of the young of this species. 



In both, the integument is transparent, tough, apparently 

 structureless, and lined by a muscular layer, which presents a 

 number of oil-globules on its surface and a patch of sarcoid 

 glanduliform prolongations in the vicinity of each extremity. 

 In U. palustris, however, it is not corrugated or striated trans- 

 versely, nor is it evidently so in the adult F. Medinensis. 



The alimentary canal is the same — that is, it consists in each 

 of a narrow oesophagus followed by a much wider intestine, which 

 pursues a straight course through the body, except where it is 

 displaced by the generative organs, to end in a short narrow 

 rectum ; but it differs in the rectum being without evident anal 

 orifice, if there be any at all in Filaria Medinensis. Again, in 

 both, the oesophagus and intestine are surrounded by their pro- 

 per peritoneal sheaths, defined by a constriction opposite their 

 point of union, while the former is also surrounded by a mus- 

 cular sheath, and the intestine by the hepatic organ up to within 

 a short distance of the rectum ; the latter is seen more distinctly 

 in the young F. Medinensis (figs. 6 /and 7 f %cc). 



Lastly, the organs of generation are cylindrical and double 

 in each — that is to say, the ovisac with its terminal ovarian 

 tubes, in Filaria Medinensis, by being symmetrical, would form 



* This diminution is much more abrupt in the illustrations than it is 

 naturally ; this is merely in consequence of using a ruler instead of the 

 hand alone for the outline, that this might have no irregularities. The 

 diminution always commences a little behind the union of the oesophagus 

 and intestine, and a little in advance of the anus for each end respectively. 



