Kinetocodium danæ n. g., n. sp. 
a new gymnoblastic Hydroid, parasitic on 
a Pteropod. 
By 
P. L. Kramp. 
(Read February llth 1921.) 
(Plate I.) 
During the summer of 1920 Dr. Joh s. Schmidt made an 
expedition on board the S/S “Dana” to the Western Atlantic be- 
tween the Bermudas and the West Indies. The numerous plankton 
samples brought home by the expedition have been handed to the 
Invertebrate Department of the Zoological Museum in Copenhagen, 
where they have been sorted by the staff of the museum. Among 
the numerous pteropods in the samples a specimen of Hyalæa 
(Diacria) trispinosa Lesueur was found to be covered with a gym¬ 
noblastic hydroid. It was forwarded to me for examination, and I 
found that it was a new species of peculiar and interesting struct- 
ure. It was very well preserved (in formalin), but as no other 
colonies were found, I had to be careful not to destroy the single 
specimen more than necessary. 
In the hope of finding more material of the species, I looked 
through the whole collection of thecosome pteropods in the posses- 
sion of the museum, and I succeeded to find some more colonies, 
collected between 1863 and 1872, and very badly preserved. One 
of them, however, is of considerable interest, as far as it proves 
the supposed parasitic nature of the species. At the same time I 
identified the other species of hydroids found on pteropod shells. 
A short account of the species in question will be found at the 
end of the present paper. 
I am indebted to Dr. Johs. Schmidt for the permission to 
publish the description of the new species in this place. 
Vidensk. Medd. fra Dansk naturh. Foren. Bd. 74. 
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