NARCOMEDUSJE — iEGINURA. 



471 



In the Malayan specimens there were 48 very minute sensory-clubs, a pair flanking each 

 of the small marginal tentacles. These were not seen in the Atlantic specimen, but were prob- 

 ably lost through accident or destroyed by the manner of preservation. There are no sensory 

 tracts, or otoporpae, on the exumbrella above the sense-clubs. 



The velum is well developed and provided with powerful ring-muscles. The mouth is a 

 simple, round opening, and the central stomach is flat and lenticular and about two-thirds as 

 wide as the bell-diameter. Peripherally the stomach gives rise to 8 principal, radial outpocket- 

 ings, each of which is deeply cleft at its median outer edge at the place of insertion of the 

 principal tentacles. There are thus 16 outermost pouches of the stomach. These peripheral 

 pouches are rectangular with rounded corners and the pouches are not plane, but buckled in 

 the gallert of the bell so that the 8 intertentacular clefts appear as if cut along the summit of a 

 divided ridge between adjacent stomach-pouches. 



There are 8 double, peronial canals in the Malayan specimens, which extend outward and 

 downward from the lappets on both sides of the 8 principal tentacles and join to torm the 

 ring-canal in each interperonial octant. There are thus 8 marginal loop-canals, the loops 

 alternating with the tentacles. These loop-canals are, however, very narrow and their ento- 

 dermal lining is degenerate. No trace of peronial canals or ring-canal could be found in the 

 Atlantic specimen and it is possible that they degenerate with growth and finally disappear. 



l°9 a - 



3°9- 



Fig. 309. — Mginura grimaldii, after Maas, in Result. Camp. Sci. Prince de Monaco. 

 Fig. 309a.— Mginopsis laurentii, after Brandt, in Mem. Acad. St. Petersbourg. 



In the 3 male specimens from the Malay Archipelago, the gonads are developed over the 

 ectodermal subumbrella walls of the gastric pouches, but in the female from the North Atlantic 

 they are very irregularly developed in patches, in some places in the ectoderm of the pouches 

 and in others at the bases of the pouches. The eggs are few in number but are of great size. 



The gelatinous substance of the bell is milky-blue, translucent, not transparent. The 

 entoderm of the stomach and pouches is deep reddish-purple and that of the tentacles light- 

 purple or colorless. 



Maas first describes a single large female specimen under the name Mginura grimaldii. 

 This was collected by the Prince of Monaco at a depth of 390 fathoms in the North Atlantic in 

 N. lat. 47 42' 41", W. long. 17 10' from Greenwich. In the following year Maas described 

 three smaller male specimens under the name Mginura weberi. These were found by the 

 Siboga at a depth of 500 fathoms in the Malay Archipelago. 



The resemblance between the Atlantic grimaldii and the Malayan "weberi" is so close 

 that the slight differences may well be due to differences of sex and age, and I am inclined to 

 unite the two species under the older name given by Maas (see text-figs. 307 and 308). Mginura 

 grimaldii is probably a deep-sea medusa and, in common with many other deep cold-water 

 forms, is of world-wide distribution. 



The Atlantic specimen was damaged, whereas those from the Malay Archipelago were 

 perfect, and on this account Maas presents a better description of the latter than of the former. 

 He presents clear figures in both cases. 



