1903] Report on some Medusae from Norway and Spitzbergen. 21 



while a third species for which I have not vet found a name has 

 another type of basal bulb. The basal bulbs of the Norwegian 

 speeimen are unlike those of the British species. It is necessary 

 to trace the outlines of the bulbs with great care and to show the 

 outer, inner, and lateral aspects. With a magnification of ten dia- 

 meters the ditferenees are easily seen. 



Aequorea norvegica has tentacdes with basal bulbs of somewhat 

 the same type as Aequorea (Polyeanna) vitrina, Gosse, but they 

 are much larger, more laterally compressed. and the external sur- 

 face is longitudinally corrugated with minute ridges and furrows, 

 instead of being smooth. Nearly all the basal bulbs of the speei- 

 men are more or less twisted, probably due to contraction, but this 

 curious twisting is not seen in the British species having their ten- 

 tacles contracted. 



The umbrella of Aequorea vitrina is very thick and globular, with 

 a large mass of jelly above the stomach, whereas the Norwegian 

 species has an exceedingly thin umbrella. The portion of the ra- 

 dial eanals bearing the gonacls is tubular and fairly narrow in 

 Aequorea vitrina, but in Aequorea norvegica the gonads are band- 

 shaped, and bilaminate, as in Aecquorea forsJcalea Fokbes. The struc- 

 ture of the oral lips is the same in both species, but they are about 

 twice as long in Aequorea norvegica. Both species have the margin 

 closely packed with tentacles, and both are without any deiinite 

 colour. 



On the sub-umbrella, over the ring canal, above each of the 

 tentacles there is a little wart-like projection, which is probably an 

 excretory pore. 



Trachomedusae. 



Hoinoeonema platygonon, Maas. 

 Plate II, fig. 2 & 3. 

 Homoconema platygonon, Maas. 1893, p. 15. Taf. I, fig. 8. 



Skjerstadfjord. 0—420 m. 2. 4. 1900. One speeimen. 

 Umbrella bell-shaped, very thin, about as broad as long. (2 

 mm.) Velum about \ 2 mm. in width. Stomach short, about one 

 quarter the length of the umbrella-cavity, with a rounded apical 

 knob. Mouth with four short lips. Radial eanals eight in number. 

 Gonads formino- a broad band extendino* from the stomach to about 



