100 



MEDUSAE. I. 



Moreover the Zoological Museum of Copenhagen possesses a large number of specimens from 

 Danish waters, where this species is exceedingly abundant right into the Belt-Sea. 



It is very interesting that Bigelow has found this North-European species in the north- 

 ern Pacific. Bigelow states that "the only noticeable separation between examples from the two 

 localities is that in those from the Bering Sea the gonads begin close to the base of the peduncle, 

 instead of at a slight distance from it, as in the Helgoland specimens, but the difference is so slight 

 that it is probably a developmental feature". I have paid attention to this statement, and I have found 

 that the authors last-mentioned supposition does not hold good ; as a matter of fact, in young as well 

 as full-grown individuals there is always some distance from the stomachal peduncle to the proximal 

 end of the gonads (see Table XIV). 



Table XIV. Dimensions of specimens of Eutonia tndicans from the above- 

 mentioned localities. 



Measurements on Danish specimens have given corresponding results with regard to the 

 distance from the base of the stomachal peduncle to the proximal end of the gonads; thus there 

 actually seems to exist a characteristic difference in this respect between the specimens from Europe 

 and those from the Bering Sea; but as they agree exactly in all other respects, this slight difference 

 hardly justifies a separation of the two forms as distinct species, unless the corresponding hydroids 

 should prove to be specifically different. 



Hartlaub gives the number of tentacles as about 150, but, as will appear from the figures in 

 table XIV, the number may amount to about 200. 



Eutonina indicans has up to now been found on the following localities in the Atlantic area: 

 east coast of Scotland: Cromarty Firth (Romanes) and St. Andrews Bay (Mclntosh); Heligoland 

 (Hartlaut)); and, if "Geryonopsis Forbesn" van. Beneden is identical with the present species, also off 

 the coast of Belgium. It is mentioned in the International Plankton-lists as occurring in the Skagerrak. 

 In Johansen and Levinsen: De danske Farvandes Plankton (1903), it has been confounded with 

 Ti'aropsis multicirrata. 



