IQ Edward T. Browne. [No. 4 



Margelopsis hartlauhii, nova species. 



Plate I. fig. 2. Plate III, fig. 3. 



Description. 



Umbrella bell-sliaped, very tliick, little higher than wide. 

 Stomach large, cone-shaped, about half the length of the umbrella- 

 cavity, with a broad, flat, quadrangular base. Mouth circular. 

 Gonads forming a circular mass round the stomach. Two tentacles 

 in each of the four perradial groups. No ocelli visible. Colour. 

 Stomach, gonads, basal bulbs, yellowish brown (in formalin). 



Size. Umbrella 3 mm. in length and 2 Va mm. in width. 

 Osterfjbrd. 200—400 m. 2G. 4. 1901. One specimen. 

 Osterfjord. 200—400 m. 13. 6. 1900. One specimen. 



Umbrella 2 mm. in length and width. 



Herløfjord. 0—400 m. 10. 9. 1900. One specimen. 



The genus Margelopsis was founded by Hartlaub (1897) for a 

 new medusa (Margelopsis haeckelii) tåken off Heligoland. In 1899, 

 Dr. Hartlaub published the interesting discovery that the medusa 

 comes from a free-swimming hydroid. 



Margelopsis haeckelii has 3 — 4 tentacles on each of the four 

 bulbs, and above the stomach thére is a conical apical stalk; the 

 remains of the conneeting canal between the medusa its hydroid. 



The specimens in this collection have only two tentacles on 

 each bulb, and the stomach has a flat quadrangular base. There is 

 no evidence of any more tentacles, and the size of gonads shows 

 that the medusa is not an early stage. 



The ex-umbrella is covered with scattered circular or oblong 

 groups of nematocysts, each group containing about a dozen 

 nematocysts. 



The tentacles are Sarsia-like in form with a few large groups 

 of nematocysts on the lower half of the tentacle (Pl. III, fig. 3). 

 The compound basal bulb is small and roundish. The gonads do 

 not occupy the whole length of the stomach, but begin a little way 

 below the base of the stomach and end just above the mouth. 

 Owing to the great thickness of the umbrella the umbrella-cavity 

 is small and varies slightly in size in the different specimens; it is 

 about half the size of the umbrella. 



Taking into consideration the thickness of the umbrella, the 

 shape of the stomach, the number and structure of the tentacles, 

 1 believe this to be a distinct species and have much pleasure in 

 naminof it after the founder of the srenns. 



