124 NEW YORK ZOOLOGICAL SOCIETY 



ing permits. It is thus possible to aid in the furtherance of 

 research far beyond anything that could be done directly by the 

 staff of the Aquarium. With an adequate building there is no 

 reason why the Aquarium should not become one of the centers 

 for biological research dealing with aquatic life. Unfortunately 

 we are at present so greatly hampered for space that it is im- 

 possible to accommodate much of this work within the walls of 

 the institution. 



Dr. G. A. MacCallum has continued his studies on the para- 

 sites and diseases of the fishes in the Aquarium. This work, 

 carried on in connection with the Departments of Pathology and 

 Bacteriology of the College of Physicians and Surgeons of Co- 

 lumbia University, has brought to light some very interesting 

 cases of fish diseases. Some of these have been tested out by 

 experiments and found to be due to pathogenic bacteria and to 

 be directly infectious. 



In regard to animal parasites, Dr. MacCallum has found 

 that ninety per cent of the angel-fishes and butterfly-fishes suc- 

 cumbed to the attacks of parasitic trematode worms of the genus 

 Microcotyle. These minute worms infest the gills and not only 

 impede the access of water by the production of slime, but suck 

 the blood of the fishes to such an extent that a fatal anaemia 

 ensues. In the same way many of the salmonoid fishes are in- 

 fested in the gill regions by species of trematodes of the family 

 Octocotylidse. 



On the other hand internal parasites are found to be much 

 less common than among wild fishes, the conditions in captivity 

 apparently tending to reduce their number very greatly. The 

 exception to this is found in the case of the striped bass (Roccus 

 lineatus) in which a parasitic round, or nemotode, worm (Echin- 

 orhynchus proteus) is sometimes found in such numbers as to 

 cover the whole of the intestinal mucosa causing intense inflam- 

 mation and preventing the proper functioning of the intestine. 

 However, this seems to be less fatal than the gill infections re- 

 ferred to above. 



The protozoan parasites known as Myxosporidia are found 

 to be much less common than in fishes from outside waters 

 though occasionally the ulcers and tumor-like swellings produced 

 by these parasites are found in the skin, in the muscles and in 

 the internal organs. But few cases of death have been found 

 traceable to this cause in the Aquarium. The fishes most fre- 



