118 BULLETIN OF THE BUREAU OB' FISHERIES. 



The distribution of cysts was in general in agreement with what has been 

 given under previous dates. In the worst cases the cysts were collected in dense 

 granular masses which filled completely several of the interspinous spaces both 

 above and below the backbone. In those which were most infested there were 

 also clusters of cysts in the head just behind the skull. A few cysts were seen 

 below the ventral end of the abdominal cavity, and a few also on the viscera. In 

 the larger fish the cysts were usually yellowish, and contained mature scoleces; in 

 the smaller fish they were for the most part white, and, so far as examined, with imma- 

 ture scoleces. In cases of slight infection the cysts were found scattered at irregular 

 intervals above and below the backbone, prevailingly behind the abdominal cavity. 

 In many of the fish which were only slightly parasitized, clusters of cysts, 20 or 30 

 in each cluster, were lodged above the body cavity but below the backbone. 



Of the 14 smaller fish, 4 had many cysts in the flesh; the remaining 10 had few. 

 One of them, the smallest in the lot, was at first thought to be free of cysts, but 

 upon a careful examination one cyst was found below the backbone about the 

 posterior third. 



The scoleces from cysts in the smaller fish, so far as examined, were immature, 

 most of them with hooks not yet developed on the proboscides, nor accessory organs 

 on the bothria; scoleces from cysts in the larger fish had hooks on the proboscides 

 and accessory organs on the bothria. 



The cysts vary somewhat in size, but the usual diameter was from 0.5 to 0.7 

 millimeter. The blastocysts have the parenchyma filled with relatively coarse 

 calcareous bodies. The calcareous bodies in the scoleces are numerous, but very 

 much smaller than those of the blastocysts. 



August 30. — Sixty-nine fish were examined. These were taken in a fish pound 

 at Nomans Land on the 29th. Each fish in this lot was split open so as to expose 

 the vertebrae, with the dorsal and ventral vertebral spines. Details of infection are 

 given in the table below. In general, it may be said that practically every fish har- 

 bored parasites in the flesh. In the few cases where no parasites were seen, it is to 

 be noted that what is meant is that no parasites were seen in the median section of 

 the fish. In a few of the fish in which at first no cysts were seen, further search by 

 scraping off some of the flesh brought one or more cysts into view. The smallest 

 fish had fewest cysts, and the cases of most numerous cysts occurred among the 

 largest fish. 



The number of cysts visible in a single interspinous space was found to be from 

 100 to 150 in two of the worst cases of infection. In such cases from 10 to 12 con- 

 tiguous interspinous spaces contained each approximately the same number of 

 cysts. This does not represent the actual number of cysts, but only those which 

 could be seen without further dissection than is involved in laying the fish open in 

 the manner described above. 



The following table contains a record of cysts seen on the exposed surface of 

 each of the 69 fish of this lot opened as above described. The number, where not 

 specifically stated, is indicated approximately by the words " few," " several," " scat- 

 tering," "many," "numerous," and " very numerous." In a few cases the para- 

 sites occurred in a single cluster, consisting of from 12 to 30 or more cysts. It should 

 be noted that in all the badly infested fish cysts occurred, often in large numbers, 

 lateral to the backbone, and immediately behind the skull. The fourth specimen 

 in the list had also a few cysts on the viscera. The viscera of only a few of this lot, 

 however, were examined. 



