of the Fishery Board for Scotland. 81 
eges produced by the mature worm had found their way by some round- 
about road to the abdomen of the fish, there to continue the cycle of their 
curious and highly interesting life-history. 
Figure 7, Plate VII., is a photograph of one of the little fishes infested 
with the parasite showing the distended abdomen, and figure 8 is the 
photograph of another fish showing the worms zn situ. 
This Cestode is apparently widely distributed; not only has it been 
recorded under one or other of its different names by European writers on 
Helminthology, but Prof. Edwin Linton mentions its occurrence in the 
abdominal cavity of the Blob, Cottus bairdw, captured in Swan River, 
Montana, August 3rd, 1891. (Proc. U.S. National Museum, vol. xx., 
p. 427, pl. xxviii. figs. 4-5.) 
Genus Tetrarhynchus, Rudolphi (1808). 
Tetrarhynchus megacephalus, Rudolphi. Pl. IV., figs. 9-10; Pl. VLI., 
fig. 3. 
1819. Tetrarhynchus megacevhalus, Rud. Entozoorum Synopsis, 
p 129 et 447. Tab. II., fig. 7-8. 
1878. Tetrarhynchus megacephalus, Van Ben., Pois. d. cotes. d. 
Belgique, p. 12, Pl. VL., figs. 8, 9-15. 
This Yetrarhynchus is one of the largest of this curious group of 
parasites; the specimen represented by the photograph (Pl. VI, fig. 3) 
measured about eighteen inches in length, and nearly half an inch in 
width. It was obtained by my son in the intestine of a Greenland Shark, 
Scimnus borealis, Flem., captured at the mouth of the Forth estuary many 
vears ago. This parasite has also been found, but in a sexually-immature 
state, in the Blue Shark, Carcharias glaucus, and some other species of 
the shark family ;* but though it appears to be limited in its distribution 
chiefly to that group of Selachians, it has also been recorded as occurring 
in other fishes, one of which is Scorpaena porcus, a Mediterranean fish. 
Van Beneden remarks that the same worm, or a near ally, has been found 
on the gills of a Sparoide, as well as in the mouth of a turbot; but, he 
adds, “ Dans cette situation le ver est errant.” T 
Tetrarhynchus tetrabothrius, P. J. van Beneden. PI. IV., fig. 11. 
1850. Tetrarhynchus tetrabothrium, van Ben., Les Vers 
Cestodes, Acad. Roy. de Belgique, Tom. XXV., p. 154, 
Pl. XVIII. 
This was obtained in the intestine of Picked Dog-fishes, Squalis 
acanthias, Linn., examined at the Laboratory in March 1902. The fishes 
had been captured in the North Sea aud landed at the Fish Market at 
Aberdeen. In these Dog-fishes this parasite was of frequent occurrence, 
being observed in nearly all the specimens examined. Van Beneden also 
records the ocurrence of this Cestode in the same species of Dog-fish, as 
well as in Mustelus vulgaris, taken off the coast of Belgium. { Olsson has 
recorded 7’. tetrabothrius from Picked Dog-fishes captured in the Skagar- 
*This Tetrarhynchus, in Dr. Baird’s catalogue of Entozoa in the British 
Museum, is recorded from a large Spotted Dog-fish, Scwllium catulus (p. 68). 
+ Les Poissons des cotes de Belgique, p. 5. 
+ Les Poissons des cotes de Belgique, pp. 6-10, 
