558 KKPORT OF COiM.MISlfclUNEK OF FISH AND FlisHEKIES. 



7.00; jjTt'atest (liainetwr, O.L'.j; diaiuetwr of liea(l,().LM>; (Uani«ter of neck, 

 O.l.J; Icngthof neck, 1.00; length of caudal si)iiie, 0.15. Female, length 

 l.l.OO; greatest diameter, 0.40; diameter of head, 0.25; diameter of neck, 

 0.17; length of neck, 1.20. Genital pore, 5 mm. from posterior end. 



These parasites were met with frequently in the trout of Heart Lake 

 and in those of YeUowstoue Lake and the river. Their favorite resting- 

 l)lace is in the alimentary cauai in the vicinity of the pyloric cceca. 



FNCYSTKU Sl'ECIMKNS Ol' D. GMHiOSA. 



This worm was also found in cysts which usually ai)peared as pedic- 

 ulatcd tumois within the body cavity of the trout. It fiequently hap- 

 pened that among the cysts of IHbothrium cordiccps, found in the body 

 cavity of the trout, there would be a few cysts which differed some- 

 what in appearance from the former. These, when opened, collapsed 

 ou account of the liberation of a thin, watery, granular fluid, in which 

 there was invariably a small iiematod worm. These proved, upon subse- 

 quent examination, to be specitically identical with the worms from the 

 alimentary canal which I have referred to T>. </lohosa. 



These cysts are easily distinguished fiom the dibothrium cysts by 

 their difference in color and resistance to pressure. The cysts of i)i- 

 hothrium cofdlcepH are white, firm, and resistant. The nenuitod cysts 

 are yellowish or flesh-colored, and are soft and yielding. Moreover, 

 they are usually suspended by a peduncle and are covered by a layer 

 of the peritoneum, which is richly supplied with ))lood vessels. The 

 worm which is liberated from the cyst is altogether disproportionate in 

 size to the containing cyst. The w^orm, even from a cyst 10 mm. in 

 diameter, may be so small as to be easily overlooked amidst the granu- 

 lar fluid w^hich escapes when the Avail of the cyst is ruptured. These 

 cysts usually occur ou the rectum or along the course of the lower 

 intestine. They are sometimes found, however, in the vicinity of the 

 pyloric cceca. 



A cyst measuring 15 by 9 by 7 mm. in its three dimensions, which 

 had been preserved in alcohol, was opened. The walls were 0.5 mm. 

 thick, and the contents were granular and whitish. The cyst was cov- 

 eied by a layer of peritoneum, which contained capillary blood vessels. 

 Tlie worm which w^as liberated was 8 mm. in length. Another cyst, 4 

 by 5 l)y 3 mm. in its thiee dimensions, contained a small male worm 4 

 mm. long. The nematods obtained from these cysts were all immature 

 and belonged to the same species, Dacnitis globosa. Sections of these 

 cysts show that their walls are made up of a number of concentric 

 layers, rather loosely connected and often poorly defined, and with 

 numerous nuclear granules in and among the layers. 



In addition to Bacnit'oi (jlobom^ and associated with it, 1 tVmnd a few 

 forins that 1 have not been able to identify. One of these, a single 

 specinu'u of which was found, is an immature form of a rather stout 

 nematod, length 14 mm., breadth 0.5 mm. It tapers gradually toward 



