32 Mr. H. J. Carter on a Bisexual Nematoid Worm. 



the latter are longer, and tlie whole resembles more the rowel 

 of a spur. Again, the liver is shorter, and the divisions of the 

 alimentary canal less defined than in the free Filaridse. 



The presence of spermatozoa in these worms, together with 

 their being all of the same size, indicates that they have arrived 

 at maturity, and are not developed in the Fly. 



As above stated, I have not seen the ova in their fully deve- 

 loped state, and I am ignorant of the future of this worm ; but 

 knowing that many Entozoa are nui'sed in one animal and lay 

 their eggs in another, it is not improbable that this part of the 

 cycle of their development may be performed in the alimentary 

 canal of the white " Paddy-bird ^^ or Crane {Ardea modesta), 

 which appears to live chiefly on the common House-fly, being 

 a constant attendant for this purpose on cattle, and at the slits 

 made in the palm-trees for the extraction of their saccharine 

 juice. 



To ascertain if F. Muscce would live in sugar-and-water, in 

 water alone, and in the former, to which in one instance gu7n 

 acacia had been added, and in another a portion of gelatinized 

 Nostoc, both to serve as a nidus to nestle in and for nourishment, 

 several of these worms were transferred to these media respect- 

 ively, in watch-glasses sheltered in a glass-case ; but none sur- 

 vived more than a few hours, whether from change of habitat or 

 change of nourishment (which latter could not be very different 

 from that taken in by the Fly, unless a secretion from the Fly 

 itself), I am ignorant. 



At first I thought that I had discovered both the spermatic 

 cells and the ova, in certain masses of cells which exist both in 

 the lobes of the proboscis and in the head respectively of the 

 Fly, as well as about the rectum in the abdomen. But sub- 

 sequent observation proved to me that these were extensions of 

 a nucleated blastema accompanying the tracheae, and that each 

 cell was provided with a terminal branch of the latter. AVhat 

 are these cells, and what is their function ? Are they at once 

 appendages both to the tracheal and vascular systems ? They 

 differ somewhat in the lobes of the proboscis, where there are 

 two or more groups, from those in the head, and niay be easily 

 seen in both when torn to pieces and placed under a magnifying 

 power of 350 diameters. It seems strange that such remarkable 

 organs should not have been figured in connexion with the 

 elements of the proboscis of the Fly generally, which is one of 

 the commonest objects of microscopical observation. 



F. Muscce will, I think, be the first bisexual Filaria of the kind 

 on record. Schneider, however, appears to have found a true 

 hermaphrodite one in Snails, in which Filaria " spermatozoids 

 are first seen to make their appearance in the generative tube, 



