of the Fishery Board for Scotland. 



81 



eggs 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 in situ. 



This Cestode is apparently widely distributed j 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, Coitus bairdii, captured in Swan River, 

 Montana, August 3rd, 1891. (Proc. U.S. National Museum, vol. xx., 

 p. 427, pi. xxviii., figs. 4-5.) 



Genus Tetrarhynchus, Rudolphi (1808). 



Tetrarhynchus megacephalus, Rudolphi. PI. IV., figs. 9-10 ; PI. VI., 

 fig. 3. 



J 819. Tetrarhynchus megacephalus, Rud. Entozoorum Synopsis, 



p 129 et 447. Tab. II., fig. 7-8. 

 1878. Tetrarhynchus megacephalus, Van Ben., Pois. d. cotes, d. 



Belgique, p. 12, PI. VI., figs. 8, 9-15. 



This Tetrarhynchus is one of the largest of this curious group of 

 parasites; the specimen represented by the photograph (PI. 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 

 years 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 Sparo'ide, as well as in the mouth of a turbot ; but, he 

 adds, " Dans cette situation le ver est errant." f 



Tetrarhynchus tetrabothrius, P. J. van Beneden. PI. IV., fig. 11. 



1850. Tetrarhynchus tetrabothrivm, van Ben., Les Vers 

 Cestodes, I 'Acad. Roy. de Belgique, Tom. XXV., p. 154, 

 PI. 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 and 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 T. 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, Scyllium catulus (p. 68). 

 t Les Poissons des cotes de Belgique, p. 5. 

 + Les Poissons des cotes de Belgique, pp. 6-10. 



