270 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



PART I. 



1. Mustelus caiiis, Doy-jish. 



(1) July 20; one, small; stomach with fragments of crabs. Calliobothrium verticillatum (Cestodo 

 Parasites of Fishes, p. 447, pi. xxxiv, tigs. 6, 7) aud mature proglottides of Rhynchobothrium bulbifer 

 (Cestode Parasites of Fishes, p. 448) in spiral valve. 



(2) July 23; one; stomach contents not noted, probably empty. Enormous numbers of R. bulbifer, 

 young and adult together, in spiral valve. No other eutozoa noted. 



(3) July 25; one; crabs in stomach. Degenerate waxy cysts in stomach-wall. C. rerticiUatiim, 

 7, spiral valve. It. bulbifer, 23, spiral valve. 



(4) July 26; one; stomach contained a partly digested fish, probably a squeteague, which may 

 have been taken in the pool, where the dog-fish had been confined for a few days. C. verticillatum, 2; 

 E. bulbifer, 12, in spiral valve. 



(5) July 29; two; stomach contents not noted. From the spiral valve of one were obtained 19 

 E. bulbifer and 6 C. verticillatum; from the other about 50 Rhynchobothrium ttimiduliim. There was also 

 an unusually large number of small cysts in the stomach-wall. (See Notes on the Larval Ccstodes 

 of Fishes, pi. vi, fig. 6.) 



(6) July 30; two; stomach contents not noted. In the spiral valve of one there were found 3 

 R. bulbifer and 1 R. tumidulum; from the other, 11 C. verticillatum and 4 R. bulbifer. The second 

 specimen had been in the pool for .some time. 



(7) August 1; three; stomachs empty. These fish had been in the pool for several days, and 

 had been dead for some time before they were examined. The alimentary canal showed some signs 

 of decomposition. From the spiral valve of the first were obtained 26 specimens of R. bulbifer, the 

 scolices still alive and moderately active. From the second 13 specimens of the same species were 

 got and also 2 of C. verticillatum. The latter were in poor condition, the anterior segments having 

 disintegrated; the former were in good condition and still active. In the spiral valve of the third 

 were 24 R,. bulbifer and 10 C. verticillatum. These parasites were not attached to the mucous membrane, 

 but were lying loose in the contents of the intestine. It would appear that with the beginning of 

 decomposition the heads soon detach themselves from the walls of the host. 



(8) August 12; one; stomach with crabs. Spiral valve contained 12 specimens of C. verticillatum 

 and 12 of E. tumidulum. 



(9) August 19; one; taken from pool and had been dead for some time. Three or four C. verticil- 

 latum in spiral valve in poor condition. 



(10) August 24; one; the specimen had been kept in confinement for a week or more, and had 

 been dead several hours before it was examined. Nothing in stomach except mucus, and no ento/oa in 

 alimentary canal. 



(11) August 25; three; same conditions as preceding. A few fragments of R. bulbifer found in 

 spiral valve, but in poor condition. 



It may be concluded from the foregoing examples that entozoa remain living for but a few hours 

 in the intestinal tract after the death of the host. They quickly become flaccid and soon show the 

 effect of the digestive fluids, and later of decomposition. Presumably they require the presence of 

 oxygen in the intestinal blood-vessels, and as soon as this supply is cut off they quickly succumb. 

 When they are placed in normal salt solution while still active they may be kept alive for hours, and 

 by adding a small amount of nutrient material and pepsin will not only live for days but may increase 

 in size. 



2. Galeocerdo tigrinus, Leopard Shark. 



(1) August 11; one; stomach contents were sand, one pod of a string beau, and two tough masses 

 of ilesh, mainly coarse fibrous tissue, not identified. The color of these pieces was about that of fresh 

 " sea pork " (Amaroccium), and the structure something like that of the " foot " of the winkle (Syootypus). 



Mr. Vinal N. Edwards reported to me the contents of the stomach of another specimen taken on 

 August 12, but not brought into the laboratory, which consisted of a rather curious collection, 



