844. WINTERTON C. CURTIS 
the flesh of another sand shark in preference to that of a teleost, 
since there is the minimum likelihood of finding any cestode 
larvae in the flesh of a large shark; whereas a teleost may, in 
addition to its normal parasites, contain almost any thing in the 
way of a ‘xenositic’ larva. All the sharks were fed shortly before 
or after their infection, as is shown in the first half of the table. 
The latter part of table 7 shows the results when -these same 
sharks were examined for parasites, and by reference to the num- 
ber given each specimen, one may follow any one fish through 
the two parts of the table. The only shark examined soon after 
the infection is No. 1, which was found dead. In this shark, 
specimens of the §. polymorphus were found adhering to the 
surface of the shark’s stomach and to the remains of the bit of 
squeteague’s stomach in which they had been introduced. Al- 
though this specimen was not found until decomposition was 
quite in evidence, these larvae still showed some slight movements 
and had therefore survived in the stomach for a period of three 
days. Shark No. 2 died during my absence from Woods Hole 
and was so badly decomposed when found that no data were 
obtained. In the spiral valve of specimen No. 3 there were a 
very large number of young Phoreiobothrium triloculatum 
(figs. 9,10 and 11). I collected and preserved some thirty-five 
of these worms, but this number represents only a small part of 
those present. Owing to their minuteness when only the deli- 
cate posterior end can be seen protruding from between the villi 
of the intestine and the tenacity with which their powerful 
hooks enable them to retain their hold, these larvae are often 
very difficult to detach from the walls of the spiral valve, though 
they may be large enough to be easily recognized. There must 
have been present in the shark many more than I collected; for 
taking into account the ones actually seen but not collected, I 
estimated at the time that there were a good many more than one 
hundred of these young worms in this single fish. A fact of per- 
haps more importance than their numbers is that in any one shark 
they were all in the same stage of development. 
Shark No. 4 shows three specimens of C. laciniatum which are 
to be regarded as worms which survived the expurgation treat- 
