828 WINTERTON C. CURTIS 
| C. LACINIATUM 
DATE SHARKS ee oa 
| Adult | Young 
| 
TUly QO ee ee 1 34 | 50 
July SO keane 1 20 | 10 
AUgUStHl iy eeio uae weer 1 30 6 
(AUGUST som sen cea cack 1 30 50 
NOUS eon ea) le eas 1 oo | 25 
AUpUSE yee ee eee a 1 50 | 30 
During the years 1899-1910 this parasite has been used for 
study by the students in one of the courses given at the Marine 
Biological Laboratory at Woods Hole and we have always been 
able to obtain an abundant supply when several sharks were 
available. Sometimes the first shark opened has yielded all the 
material needed and it has never been necessary to examine more 
than four or five. Most of the actual counts recorded in my notes 
in 1903-04 were made upon sharks in which search was being 
made for specimens showing the early stages of proglottid forma- 
tion and for this reason the sharks recorded are perhaps those 
which seemed, when first opened, to have an abundance of the 
parasites. Linton’s records as given in the first table are there- 
fore more fairly representative. 
As a further example of their abundance, my notes record the 
examination on August 11, 1904, of ten sand sharks, taken in 
the traps on that date. Every one of the ten was infected and in 
only two cases was the number of the parasites noticeably small. 
Count was not made because it was evident that the amount of 
infection averaged substantially the same as that shown by Lin- 
ton’s record. 
From these data it is evident that one rarely finds a sand shark 
which has not some infection; and from the fact that the worms 
may be found in all stages of development, from the specimens 
just beginning to form segments to the large adults which are 
shedding motile proglottids, one may conclude that the source 
of the infection has been in contact with the sharks within a quite 
recent period, if, indeed, it is not acting upon them throughout 
the summer. 
