200 Transactions. — Zoology. 



10 lbs. to 20 lbs. in weight, springing out of the water. These seemed also 

 to be dark hi colour as they rose to view in the air, leaping to a height of 

 four or five feet. I may mention here that the previous night on visiting 

 the beach I heard many trout splashing about and out of the water, so 

 nightfall with its keener air did not put a stop to their gambols, or irrita- 

 tion, whichever it might be. Eeturning towards the point where I had 

 seen ths diseased six-pounder, I observed one with its tail-fin out of the 

 water, belly up and head on the bottom, in shallow water, drifting ashore. 

 Wading in I seized it by the tail and easily ran it out and laid it on the 

 shingle. As it was nearly dead I did not kill it, and in a few minutes it 

 succumbed. It was evidently the same trout that I had been watching 

 half an hour before, as it had the identical fungus marks I had been ob- 

 serving, and it weighed 7| lbs. The fish was a female trout, fat, but dark 

 in colour, badly spotted on dorsal and all the other fins with fungus ; the 

 gills were full of it, and a tuft hung out of the right side of the mouth, 

 while the back and sides had a number of distinct marks or patches, some 

 appearing as if due to the mucous covering having been eaten away by the 

 disease. The margin of right opercula and origin of right pectoral fin were 

 also eaten away. Lying on the beach near the creek mouth I saw the 

 skeletons of two other trout which had evidently come ashore after death. 

 Examination of the Diseased Trout. 



The same evening, twelve hours after getting this trout, Dr. Douglas, of 

 the Wakatipu Hospital, and I made an examination of it. Immediately 

 after death it had visibly swelled, and continued to do so till the abdomen 

 became very much distended — a thing which never occurs with healthy 

 trout. On opening it we found it full of ova nearly ripe, the roe-lobes 

 having a hard appearance ; pyloric caeca fatty, but not healthy ; stomach 

 quite empty, and air-bladder very much swollen with gas. The other 

 viscera seemed healthy. A number of the blood-vessels lining the abdominal 

 wall were full of coagulated blood, but that is not unusual. The teeth on 

 body of vomer were gone and the gills were of a dull purplish hue. In 

 attempting to remove a patch of fungus from the gills it could not be 

 separated, so firmly had the roots taken hold, and the tissues came away 

 easily with it. The gills, in fact, were rotting. 



A small portion of fungus placed under the microscope showed a form 

 and structure remarkably like Saprolignia ferax (figs. 1 and 2, pi. XXIII.), 

 and, so far as I can judge, apparently the same disease ; but of that I can- 

 not be positive. Plenty of long sacs full of spores were present, with 

 innumerable free cells floating about them, and some in circular sacs 

 resembling Ogonium (or spherical sac containing spores and supported by 

 short stems), but destitute of stems. No sacs were seen in the protoplasm 



