HARDWICKE'S SCIENCE-GOSSIP. 



I discovered that what I bad thought were fibres of 

 connective tissue, were in reality small worm-like 

 bodies, which were slowly moving about in the 

 fluids and organs of the fish. On removing the 

 visceral mass by dividing the oesophagus and aorta 

 close behind the gills, and tearing it away from its 

 attachments, I placed it under a two-inch lens, and 



Fig. 3. Parasitic worms in fish. 



found that the parasite was distributed all over and 

 through it. Picking out several of them with a 

 bent needle, I placed them on a glass slide, put a 

 small quantity of the fluids of the fish with them, 

 placed over them a cover glass, and examined them 

 with a two-inch lens. Their general appearance 

 resembled those of the hsematoid class of parasitic 



f not however make out any sexual differences, for 

 all that were examined were apparently immature 

 males. Yet there must have been a female hidden 

 somewhere in the host, for I found two encysted 

 worms on the edge of the liver, which were picked 

 off with a bristle, only one of which was success- 

 fully mounted and drawn (see fig. 4). In the free 

 worm there was a small opening like a mouth at the 



Fig. 4. Encysted parasitic worm. 



worms. Eig. 3 gives a good general idea of their 

 form. Taking the liver by itself, I pressed it well 

 between two slides, and found several of the para- 

 sites. All the other organs were examined iu the 

 same way, and, with the exception of the air- 

 bladder, all of them contained the worm in abun- 

 dance. 



Remarks. — These worms appear to be identical 

 with the genus Prosthecosacter, as described by 

 Professor Cobbold, and I feel inclined to believe 

 that they agree with Prosthecosacter minor. I could 



^MrajW 



Fig. 5. (Esophagal ganglion of worm. 



apex of the truncated head ; an oesophagus was 

 plainly visible, with what I took for a collar of 

 nervous matter, embracing it externally. I presume 

 this is the oesophageal ganglion (see fig. 5). The 

 alimentary canal was freely suspended iu a cavity, 



Fig. 6. Anal orifice of parasitic worm. 



sometimes assuming a convoluted appearance, and 

 had an anal orifice situated in the centre of the end 

 of the tail, as seen in fig. 6, where the contents of 

 the rectal end are seen to be extended. In this 

 figure may be seen a fine corrugated line running 

 clown on the outside of the alimentary canal, which 

 I suppose is one of the canals of the water vascular 

 system. 



This short description of a haematoid worm 

 inhabiting, and no doubt killing the host, is of some 

 little interest, because of the vast consumption of 

 marine fish as food by the public, who as a rule are 



