78 Part ITI.—Twenty-siath Annual Report 
Several young specimens of a Distomum, which closely resemble 
the immature D. cestoides from the Skate, were found encysted on 
the walls of the stomach of a Witch Sole, Plewronectes microcephalus, 
captured in the Moray Firth. There were several cysts observed, and 
all those examined contained only young Distomids—in some cases one, 
in others two examples. Two of the young forms and one of the cysts are 
shown on Plate VII., figs. 5 and 6; the figures are about twice the natural 
size. 
Fishes form a considerable proportion of the food of large Skates, and 
probably the Witch Sole, which lives in moderately deep water, some- 
times becomes the prey of these large Plagiostomes. Should this happen, 
the encysted Distomids will be liberated and reach maturity in the 
alimentary passages of their new host. 
Several other large Distomids besides the one here referred to have 
been recorded as the parasites of various fishes. One of the largest, 
perhaps, was that obtained by Nardo in 1827, from a fish captured in the 
Gulf of Venice. Two specimens of this parasite were obtained, one of 
which measured five inches in length.* This species was named by Nardo 
Distoma gigas, but Dr. Cobbold, the English authority on Entozoa, 
considered that Nardo’s Distoma belonged to the same species as that 
described by Rudolphi in his history of Entozoa published in 1808, under 
the name of Distoma clavatum.* The species described by Creplin as 
Distomum veliporum is also a moderately large one. It is said to attain 
a length of three inches, and as it has been recorded from the same 
species of Skate as those described above,f I was at first under the 
impression that those found by me might belong to that species. 
Our specimens, however, agree better with van Beneden’s figure in his 
work Les Poissons des cotes de Belgique, p. 17, Pl. IV., fig. 9., than with 
the description of D. veliporum in Diesing’s Systema Helminthum. 
I have therefore provisionally ascribed our specimens to van Beneden’s 
species Distomum cestoides, 
It may be noted here that D. veliporwm is apparently a widely-dis- 
tributed species. Prof. E. Linton, of Washington and Jefferson College, 
U.S.A., has described in the proceedings of the U.S. National Museum 
(vol. xx., p. 521) a large Distomum from the stomach of a “ Barndoor 
Skate,” Raia lovis, captured at Wood’s Hole, Massachusetts, which he 
ascribes to this species. This specimen, however, like that of D. cestoides 
recorded by van Beneden, was incomplete. The specimen recorded here 
is in fairly perfect condition. 
CESTODA. 
Genus Bothriocephalus, Rudolphi (1808). 
Bothriocephalus proboscideus, Rudolphi. Pl. V., fig. 4. 
1808. Bothriocephalus proboscideus, Rud., Entoz. Hist. Nat., 
vol. iii., p. 39. . 
1850. Dibothrium proboscidewm, Dies., Syst. Helminth., 
vol. i., p. 590. 
This Cestode was obtained in the intestine of a Trout captured in Loch 
Tay, in August 1901, by my colleague, Dr. H. C. Williamson. The 
* See ‘‘ Parasites,” by T. Spencer Cobbold, M.D., p. 460; and ‘‘Systema 
Helminthum,” Diesing, voi. ii., p. 366. 
+ Catalogue des Poissons des cotes de la Manche dans les environs de Saint- 
Vaast, par M. A.-E. Malard. Bull. Soc. Philomathique de Paris, 8 ed., Ser. t. I1., 
p- 70 (1890). 
