ölet coalleckHon of? Arctic Hydroids formed by Dr: Stux- 
berg, the zoologist accompanying Baron Nordenskiöld 
on his foreatv cimoumnavigatnon IN the Vega, contams no 
very conspicuously new or remarkable forms, although much 
of it was got in seas never searched by naturalist before. 
Yet it is not without interest, for it extends greatly the 
known area of distribution of many forms, and contains spe- 
cimens of several difficult and little-known species. And it 
links together the comparatively well-known Hydroid faunas 
bölfbarentst Icea "andföthie N. Atlantie om the one hand, and of 
Bering Strait and Alaska on the other. 
The general similarity between these two faunas is very 
iStTeat.  Ihe same genera are characteristic of both, and the 
same types of species; though absolute specific identity is 
comparatively rare at the two extremes. 
Obelia longissima, Gonothyrea hyalina, Filellum serpens, La- 
foéa fruticosa, probably Sertularella gigantea, Sertularella tricuspi- 
data, appear at both limits, the last species only showing slight 
characteristic differences. 
Sertularia abietina at the eastern limit seems to be repre- 
sented by S&S. variabilis at the western; Thuiaria articulata by 
T. turgida. While the limited group of Thuiarians to which 
"the so-called Sertularia cupressina and argentea belong, is cha- 
racteristie of the whole area, these species being replaced 
kommande thetmesteby fi Kege, 1. sp, I. plumosa, and ino: 
busta.! 
In many cases our collections show no such transition. 
Our common N. Atlantic Campanularia verticillata is exceedingly 
se GC lackels Alaskan OM circula: and neverthelesstthe Mega 
collection only brings the former species from an extreme N. W. 
BHuropean statnon, and has neither of tihiese nor any similar 
form from intermediate points. 
1 Also T. (S.) sumilis, T. cupressoides, and S. thuiaroides, elosely allied 
Alaskan species described by Clarke but not represented in the Vega col- 
lection. 
