Mr. H. J. Carter on Dracunculus." 29 



connected, exact, and complete description of it — which does not 

 now exist. Besides, this could never have been acquired without 

 a study of the microscopic Filaridae which are to be found in the 

 waters of the locality ; while this study, again, has elicited facts 

 which will be found acceptable both in physiology and natural 

 history generally. Advantage also has been taken of the ana- 

 tomy of the young Guinea-worm to confirm the existence of 

 what otherwise might be doubted in the adult ; and this, again, 

 has afforded means of comparing the latter with the anatomy of 

 the Tank-worm, for the purpose of pointing out the great resem- 

 blances between the two, and accounting for the modifications 

 in form, &c., of Dracunculus, which appear to be induced by the 

 circumstances under which it is developed. 



The illustrations are numerous, and comprise, in the first 

 plate, those of Dracunculus ; the second plate is entirely devoted 

 to a typical display of the organology, ovology, and spermatology 

 of the microscopic species called the " Tank-worm '/' and the 

 third contains the forms of most of the other microscopic Filaridae 

 which have been observed. All the representations have been 

 drawn after nature with great care, but with a leaning towards 

 mathematical accuracy which renders them stiff and formal, 

 though not the less effective for demonstrating the facts which 

 they are intended to record. 



I shall first describe the form and anatomy of Dracunculus, 

 and then go to that of the Tank-worm ; after which the other 

 species of microscopic Filaridse will be given, with some obser- 

 vations on them generally ; and lastly, the whole considered 

 with reference to the origin of Dracunculus. 



The species of Dracunculus which occurs in the human sub- 

 ject in the island of Bombay, and probably in all India, is that 

 which has been called "Filaria Medinensis," or " Guinea- worm ;" 

 and under this appellation it will be henceforth designated. 



Filaria Medinensis, Gmel. PL I. fig. 1. 



Female. Long, narrow, cylindrical, of equal size throughout, 

 except towards the extremities, which are slightly attenuated. 

 Smooth, white or colourless, unstriated transversely to the un- 

 aided eye, presenting two transparent and two opake lines run- 

 ning throughout the body, corresponding to the muscular bands 

 and their intervals respectively. Anterior extremity or head 

 (fig. 4) obtuse, round, furnished with two papillae which are 

 scarcely visible to the unaided eye, presenting, under a high 

 microscopic power, a punctiform hole or mouth in the centre, 

 surrounded by a smooth-bordered quadrangular space, on each 

 side of which is a papilla, two of which papillae are large and 

 prominent, viz. those first mentioned, and situated above and 



