A CESTODE PARASITE IN THE FLESH OF THE BUTTERFISH. 117 



cysts. The maximum number occurred in a region between the seventh and 

 twelfth vertebra from the tail. It was estimated that 1,200 cysts were exposed in 

 a fish 21 centimeters in length laid open as shown in fig. 1, but since many of the 

 cysts could not be seen, the actual number in the fish was much greater than this. 

 The region above the backbone, while not having so many cysts as the ventral 

 region, still had large numbers. These were most abundant between the dorsal 

 spinous processes of about the seventh to the tenth or twelfth vertebra from the 

 tail, and in the thoracic region, about halfway between the backbone and the 

 dorsum. Both above and below the backbone cysts were scattered more or less 

 thickly for a distance of 25 to 30 millimeters from the vertebra. In those tish 

 which had but few parasites the cysts were widely scattered both above and below 

 the backbone. In some places cysts were seen lying as close as it was possible for 

 them to lie in spaces as much as 5 millimeters square, the clusters having a thickness 

 of 2 or 3 millimeters. 



August 17. — Two fish, 187 and 200 millimeters in length, respectively, were 

 examined and each found to be badly infested. Another, 75 millimeters in length, 

 was examined at the same time, but no cysts were found in its flesh. 



August 18. — Eight fish examined. Two of these. 50 and 75 millimeters in 

 length, respectively, had no cysts in the flesh. The others, 125 to 175 millimeters 

 in length, each had cysts in the (lesh. These cysts, as in other instances observed, 

 were most abundant about the posterior third on the ventral side of the backbone 

 between the ventral spines. 



August 24- — Fourteen fish from 175 to 200 millimeters in length, and one 100 

 millimeters in length, were examined. Cysts were numerous in all the larger fish, 

 and very numerous, i. e., several thousand, approximately, in all hut two or three of 

 the fourteen. In the small specimen only two cysts were found, although careful 

 search was made. One of these was a I it lie hack of the middle and near the ventral 

 side of the backbone; the other was at about the posterior third and halfway between 

 the backbone and the dorsal surface of the body. These two cysts were ivory while. 

 One of them contained a scolex; in the other a scolex had not yd developed. 



In the badly infested fish cysts were most abundant along the backbone between 

 the vertebral spines. The cysts were most abundant on the ventral side of the 

 backbone in most of the fish. A few of the fish had the cysts massed in a space 

 two or three centimeters in extent on the ventral side of the backbone, a short 

 distance behind the abdominal cavity. The cysts in a few other instances were 

 most abundant about the middle of the body — as many above as there were below t he 

 backbone. The color of the cysts, except in the case cited above, was yellowish, enough 

 to make a fairly sharp contrast with the llesh of the host. Apparently the larger fish 

 had been affected with these llesh parasites for some time. Most of them were in 

 rather poor condition. So far as examined it was found that the usual immature 

 nematodes were present on the abdominal viscera, but not in unusual numbers. 



August 26. — Seventy-three fish examined. Of these, 57 ranged in length from 

 190 to 210 millimeters: the remaining 14 were from 110 to 162 millimeters in length. 

 Cysts were found in the flesh of every one of the 73. They were very numerous 

 in 51 of the 57 larger fish. Even those of the 51 which were least infected still 

 harbored approximately several thousand cysts. The remaining 6 of the larger 

 fish had few cysts — that is to say, upon splitting one of them only a few scattering 

 cysts were seen, or, in a few cases, clusters with the cysts somewhat scattered. 

 The number of cysts visible in a split fish, in these slightly parasitized specimens, 

 varied from a dozen or less to 50 or more. 



