NARCOMEDUSAE 69 



The only previous record from the Atlantic was near the Canary Islands, where 32 specimens were 

 taken by the 'Atlantide' Expedition (Kramp 1955). 



Apparently the species occurs in the upper layers. On some few occasions (in the South Atlantic 

 and the South Pacific) it was taken in vertical hauls between about 300 m. and 100 m., but the 

 majority of the other hauls were made from various depths to the surface. At St. 100, near the Cape 

 of Good Hope, several specimens were taken in the surface 5 m. 



Remarks on the morphology. In well-preserved specimens the central mass of jelly is usually 

 thick and fairly highly vaulted, smooth; an indication of keels may occasionally be present below the 

 otoporpae, but never continued above these latter. The ventral wall of the stomach is sometimes so 

 strongly contracted that the mouth is a small opening. The interradial pockets, in which the gonads 

 are developed, are usually quite simple, flatly rounded, rarely hemispherical, occasionally slightly folded, 

 forming two or three short lobes. They may sometimes be discerned in specimens only 8-1 1 mm. 

 in diameter, but frequently no traces of pockets are seen, even in much larger specimens, especially 

 if the state of preservation is bad. When the gonads are particularly well developed, they are not 

 restricted to the interradial pockets, but constitute a continuous folded band along the entire outline 

 of the stomach, comprising the interradial pockets as well as the radial incurvations in the tentacular 

 radii. The marginal lappets are usually about as long as broad, square or evenly rounded, rarely 

 pentagonal or semi-circular. Their relative length is not merely dependent on the state of contraction, 

 but also to some extent on the number of lappets, being somewhat elongated when there are many, 

 short when there are few; in one specimen, 16 mm. in diameter with only seven tentacles, the lappets 

 were only half as long as broad. The number of marginal clubs on the lappets is somewhat variable; 

 sometimes there are only 3, and occasionally I have counted as many as 9 or 10 on each lappet, but 

 as a rule there were 5 or 7, almost always an odd number. The otoporpae are short and narrow, 

 about twice as long as the width of the transverse portion of the peripheral canal. The number of 

 tentacles varies between 7 and 17 (see below). 



The conformation of the peripheral canals is very characteristic and may be recognized even m 

 mutilated specimens (PI. VI, fig. i). The transverse portion along the external edge of the lappet is 

 fairly narrow, the lateral portions along the peronia are considerably broader, especially m their 

 proximal parts, tapering in width towards the external margin. When measured mid-way between 

 the basis and the external edge of the lappet, each canal is about one-fifth as wide as the entire lappet. 

 In this respect P. martagon differs distinctly from P. laevis and P. clara. 



In the present collection 85 specimens could be measured, varying in diameter between 3 mm. and 

 30 mm. The number of tentacles in specimens of different sizes will be seen from the following table : 



It appears from these figures that within each size-group the variation in number of tentacles is 

 rather considerable, but each specimen attains its final number of tentacles at an early stage of develop- 

 ment and only occasionally one or two are added later on. The number of 8 tentacles was found 



