Helminth Fauna of the Dry Tortugas. 185 
27. Rhynchobothrium sp. 
(Plate 11, figs. 83-87.) 
A larval tetrarhynch was obtained from a cyst on the viscera of a 
Spanish sardine (Clupanodon pseudohispanicus), on July 9, which I have 
not been able to refer to any described species. 
Bothria about as long as broad, emarginate on posterior border, ap- 
proaching each other in front, divergent behind. The neck is cylindrical, 
increasing slightly in diameter to base, with a slight hint of a fold at the 
base, minutely spinose. Sheaths very densely coiled spirals; bulbs moder- 
ately short, arcuate; proboscides relatively long; hooks small, but of several 
different kinds. ‘The most of the hooks are slender, those at the base sharp- 
pointed and slightly arcuate. Elsewhere they are slender, straightish, with 
a tendency to have abruptly recurved tips. There are a few, two or three, 
longitudinal rows of shorter hooks. 
Dimensions, in millimeters, of specimen mounted in balsam: Length 
of head and neck 0.88; length of bothrium 0.17; diameter of head 0.22; 
of neck, anterior 0.14, base 0.20; bulbs, length 0.19, breadth 0.05; probos- 
cides, length (estimated) 1, diameter at base, exclusive of hooks, 0.017; 
length of longest hook 0.01. 
28. Otobothrium crenacolle Linton. 
Report U. S. F. C., 1887, pp. 850-853, plate x11, figs. 9-15, plate xiv, fig. 14. 
Bull. U. S. F. C., 1880, pp. 273, 428. Bull. Bureau of Fisheries, vol. xxiv, 
Pp. 331, etc., encysted in 13 hosts, adult in 1. 
Two specimens of this species were found in the spiral valve of a cub- 
shark (Carcharhinus platyodon), July 12. 
Dimensions of living specimen, in millimeters, flattened: Length 2.24; 
head, length 0.28, breadth 0.30; neck, length 0.16, breadth, anterior, 0.16, 
at base 0.19; bulbs, length 0.084, breadth 0.046; breadth of body behind 
neck 0.12; last segment, length 0.86, breadth 0.21. 
This species is of very wide distribution. At Beaufort it was found 
encysted in thirteen species of teleosts and adult in one selachian. At Woods 
Hole it is of frequent occurrence encysted in a variety of teleosts and adult 
in the hammerhead shark. It infests the muscles of the common butter-fish 
(Poronotus triacanthus) to an unusual degree. 
29. Synbothrium filicolle Linton. 
Report U. S. F. C., 1887, pp. 861-862, plate xv, figs. 2-4. Proc. U. S. Nat. Mus., 
vol. XIx, p. 819, plate Lxviu, fig. 10. Bull. U. S. F. C., 1800, pp. 275, 413, 
414, etc., noted in 10 hosts. Bull. Bureau of Fisheries, vol. xxiv, p. 333, 
etc., noted in 9 hosts. 
One adult of this species was found in the spiral valve of the sting- 
ray (Dasyatis say), July to. 
