On åa new Gymnoblastic Hydroid (Zchthyocodium 
sarcotretis) epizoic on a new Parasitic Copepod 
(Sarcotretes scopeli) infesting Scopelus glactalis Rhdt. 
By 
Hector F, E. Jungersen. 
(With PL I and IL) 
Åbout two years ago one of my pupils, Mr. Blegvad — 
now Cand. mag. — handed over to me a specimen of Scopelus 
glacialis with a most remarkable parasite, asking me what the 
latter might likely be. The fish with the strange guest had been 
Captured in August or September 1906 in the depth of the Atlantic 
off the S. W. coast of Ireland by the Danish steamer Thor”, on 
an investigation cruise in which Mr. Blegvad took part as assistant 
naturalist. I was not able to answer the question immediately and 
laid the specimen aside for closer examination later. This examin- 
ation I have only recently found time to make. The parasite (Pl. I, 
Fig. 1) at first sight appears made up of a stem and a large number 
of branchlets. The stem is stout, when viewed with a strong lens 
densely striated transversely; it narrows somewhat abruptly into a 
Short slender stalk inserted into the body of the fish. Both sides 
and the face looking towards the fish are covered with a great 
number of quite soft structures resembling papillæ; the whole thing 
bears a superficial likeness to an "Eolis”. At first I thought it 
might be a Pennella, but the soft and irregularly grouped pa- 
Pillæ did not show any great likeness to the firmly cuticularized, 
branched and symmetrically arranged appendages of a Pennella. 
Closer examination of some of the larger and stouter "papillæ”, 
which had fallen off from the sides of the stem, revealed the 
structure of Medusæ, and a slender ”fpapilla” from the inner face 
Vidensk, Meddel. fra den naturh. Foren. Bd. 64. I 
