AKT. 21. PARASITES OF SHARKS AND SKATES LINTON. 66 



Collections on dates other than those occurring between June 27 

 and September 3 were made by the late Vinal N. Edwards. 

 Adult stage. 

 Carcharhinus ohscuims. 



1916, July 26 : 1 scolex ; probably lately introduced with food. 



Dasyhatis centrura. 



1903, October 5 : 2 scoleces with strobile beginning on one of them ; 

 length of scolex, 6 mm, ; length of young strobile, 13 mm. 



1914, August 1:1. 



Narcacion nohilianus. 



1905, August 7:1; length 52 mm. ; posterior segments, length 3.5, 

 Ireadth, 1. August 12: 1, scolex only. 



1914, July 13 : 1. scolex only. 



Uaja diaphanes. 



April: 1 to 17, in 38 skates, 13 dates, 3 different years; ripe joints 

 on 7 dates. 



May: Recorded on 27 dates, in 7 different years, 74 skates ex- 

 amined ; largest number from one skate, 35 ; not found in all skates 

 examined, but record does not indicate the number in which no 

 cestodes were found ; ripe joints noted on 10 dates. 



June: 1 to 16, in 13 skates, on 9 dates, in 6 different yeare; ripe 

 joints noted on 6 dates. 



1905, August 9 to 25 : 1 to 14, from 7 skates on 7 dates; ripe joints 

 noted on 2 dates. 



1907, August 30: 5 skates examined; many cestodes in 3, few in 

 2, 160 in all. 



September: 4 dates, 3 different years, 54 skates examined; ripe 

 joints noted on 2 dates; record does not always show the number of 

 skates in which cestodes were found. Thus, the record for September 

 27, 1911, is 27, and numerous free segments from 43 skates. 



October: 21 dates, 8 different years, 84 skates examined; ripe 

 joints noted on 10 dates. The record usually gives the number of 

 skates examined on a given date with, sometimes, the number of 

 cestodes found in particular individuals. As a rule the label with 

 the specimens bore only the name of the host, the number of fish 

 examined, and the date. Mr. Edwards also kept a journal in which 

 the character of the food of the fish examined for parasites was 

 noted. The smallest number of cestodes noted for one skate in this 

 month was 1, the largest, 108. On one date 40 skates were examined, 

 and cestodes found in 10; on another date cestodes were found in 

 35 out of 20 skates examined. 



November : 3 to 45, from 13 skates, on 8 dates, in 2 different years ; 

 ripe joints noted on 7 dates. 



