PROCEEDINGS OF THE UNITED STATES NATIONAL MUSEUM 
issued (a 
SMITHSONIAN INSTITUTION 
U. S. NATIONAL MUSEUM 
Vol. 92 Washington : 1942 No. 3135 
SOME CESTODES FROM FLORIDA SHARKS 
By Asa C. CHANDLER 
Tue four cestode worms herein reported were collected by Stewart 
Springer, of the Zoological Research Supply Co., from sharks taken 
off the Gulf coast of Florida near Englewood. Two of them— 
Dasyrhynchus insigne and Nybelinia palliata—have previously been 
reported from the same or related hosts at Woods Hole, Mass.; 
Diploétobothrium springeri represents a new genus and species and is 
the second tetrarhynchidean known with double sets of reproductive 
organs; and the other, Thysanocephalum rugosum,' is a new species 
from the same host as 7. thysanocephalum. 
Genus THYSANOCEPHALUM Linton 
THYSANOCEPHALUM RUGOSUM, new species 
Figure 2, a-d 
Two specimens of this worm were obtained from the spiral valve 
of a tiger shark, Galeocerdo arcticus; one had a total length of 48 cm. 
and had mature but not ripe segments at its end, while the other was 
only 14 cm. long and showed no evidence of segmentation. Neither 
specimen showed any trace of the true scolex such as occurs in the 
other species of Thysanocephalum, but the general character of the 
worm, the structure of the pseudoscolex, and the anatomy of the 
mature segments leave no doubt concerning the close affinity of this 
worm with members of the genus Thysanocephalum. It can only be 
conjectured that the true scolex has been lost or atrophied in these 
specimens. 
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