AKT. 21. PARASITES OF SHARKS AND SKATES LINTON. 73 



Stenotomus chrysops. 



1904, August 11:1 cyst on viscera, 6 fish examined. 



1909, July 26 : 4 cysts from muscles back of head, near back-bone ; 

 plerocerci, in sea water, 8 to 12 mm. in length, and 3 to 4 mm. in diam- 

 eter, ivory-white, enclosed in very thin cysts; general outline pyri- 

 f orm with scolex protruding from larger end ; scolex moderately ac- 

 tive, plerocercus slightly contractile ; contractile bulbs 0.9 by 0.4 mm. 

 compressed, retractile muscle attached to base of bulb. Collected by 

 Dr. C. W. Halin. 



Tautoga onitis. 

 1911, August 15 : 1 cyst on viscera, 1 fish examined. 



Tautogoldbrus adspersus. 



Collected in 5 of the years from 1902 to 1910 : 1 to 4 cysts on each 

 date, on viscera. On 1 date in July, 1 cyst, collected by Dr. C. W. 

 Hahn ; 3 dates in August, 1 on each of two dates, 4 on the other, on 

 viscera, 35 fish examined ; 1 date in September, 2 cysts, on viscera, 4 

 fish examined ; 1 date in October, 2 cysts on viscera, 5 fish examined. 

 Urophycis chuss. 



Collected in 10 of the years from 1901 to 1915 : Cysts usually pyri- 

 form, most of them small, 2 mm., more or less, in greatest diameter, 

 occasionally one as much as 5 mm. in diameter; on viscera and in 

 intestinal wall; in some cases degenerated. For example the record 

 of November 3, 1911, is: A few cysts, among them clusters of very 

 small cysts, 0.5 mm., or less, in diameter, with yellowish, waxy degen- 

 erate tissue; in some the contents were in part calcified. In one of 

 these degenerate cysts, the hooks of E. impaiispine were identified. 

 On 4 dates in May, 1 to few cj'sts on each date, 22 fish examined ; 1 

 date in June, 3 scoleces and 1 small cyst, 10 fish examined; 3 dates 

 in August, numerous cysts, 10 fish examined; 5 dates in October, 1 

 to 5 cysts on each date, 50 fish examined; 18 dates in November, 1 

 to few cysts on each date, 288 fish examined. 



Vropliycis regius. 



1911, November 6: 1 pyriform cyst, 3.5 by 2 mm., 1 fish examined. 

 November 8 : 2 small cysts, 3 by 1.5 mm., 1 fish examined. 



Urophycis tenuis. 



Collected in 8 of the years from 1907 to 1916, inclusive: Cysts, 

 usually pyriform, on viscera, and in intestinal wall, often numerous, 

 in some cases degenerate; usually about 5 mm. in greatest diameter, 

 but occasionally larger, and not rarely smaller. On 1 date in April, 

 8 cysts, 1 fish examined; 2 dates in May, 3 on one date, few on the 

 other, 4 fish examined; 2 dates in June, 3 on one date, few on the 

 other, 3 fish examined ; 1 date in August, few cysts, 3 fish examined ; 

 13 dates in October, 1 to numerous cysts on each date, 34 fish ex- 



