820 WINTERTON C. CURTIS 
The material was collected and the experiments performed 
during the summers of 1903 and 1904 at the Marine Biological 
Laboratory and the United States Fisheries Bureau Laboratory 
at Woods Hole, Mass., and I am indebted to those in charge 
of these institutions for substantial aid in the prosecution of the 
work. 
METHODS 
The sharks used for infection and the squeteague from which 
the specimens of the Scolex polymorphus were obtained, were all 
taken during the summer months in the fish traps near Woods 
Hole. The sharks were marked by means of numbered copper 
tags, fastened to the dorsal fin and were kept in wooden fish cars 
about 5 x 6 x 14 feet, several of which were fastened together to 
form a float upon which much of the work could be conveniently 
carried on. At the outset it was necessary to devise some appa- 
ratus by which the animals could be held securely in a position 
convenient for any necessary operation and which could be manip- 
ulated with safety by a single person. The holder which was 
finally constructed consisted of a trough about four and one-half 
feet in length, formed by nailing two boards together and across 
their ends two shorter strips after the fashion of a farmer’s ‘pig- 
trough.’ The top of this trough was covered by a hinged lid 
which, when fastened down, left the head and tail exposed but 
held the body of the fish securely along the greater part of its 
length. The cross piece of one end was hinged to the surface of 
the float where the holder was being used and to the free end was 
hinged a support, which, when swung out, held the contrivance at 
any desired height as the free end was lifted toward the upright 
position. By working rapidly, it was possible, with the fish 
thus held securely, to complete the necessary treatment in a few 
moments, and any more elaborate apparatus providing for the 
irrigation of the gills seemed unnecessary, since the sharks gave 
no indication that their vitality had been impaired by this brief 
exposure to the atmosphere. In operation this holder was safe 
and in every way satisfactory. The shark was dipped up with 
