NARCOMEDUSAE 73 



Pegantha clara R. P. Bigelow 1909 

 (PI. VI, fig. 3, text-figs. 12, 13) 



1908 Poly colpa for skali Vanhoffen, p. 56 {non Haeckel). 



1909 Pegantha clara R. P. Bigelow, p. 80. 2 figs. 



1909 Pegantha smaragdina H. B. Bigelow, p. 90. PI. 14, figs. 1-2; PI. 19, figs. 1-9; Pis. 22-6. 



1912a Polycolpa forskali Vanhoffen, p. 391. 



19126 Polycolpa forskali Vanhoffen, p. 32. 



1918 Pegantha clara H. B. Bigelow, p. 397. 



1938 Pegantha clara H. B. Bigelow, p. 134. 



1940 Pegantha clara H. B. Bigelow, p. 305. Figs. 15-16. 



1947 Pegantha clara Kramp, p. 33. PI. 4, fig. 7; PI. 5, figs. i-io. Text-fig. 12. 



1950 Pegantha clara + smaragdina Berrill, p. 299. Figs. 4A-E and f-k. 



Occurrence: Stns 85, 247, 284, 678, 689, 697, 698, 701, 707, 708, 1370, 1373, 1576, 1585, 1749, 2066, 2068, 2069. 

 (For details of position, date, etc., see Table i, p. no.) 



St. 1749 is in the middle of the Indian Ocean between South Africa and AustraUa; Stns 1370, 1373, 

 1576 and 1585 are off the east coast of Africa; the other stations are scattered over the Atlantic Ocean 

 between 30° 46' N. (St. 2069, north of the Canary Islands) and 37° 20' S (St. 247), (see chart, text- 

 fig. 12). 



Presumably the species was mainly taken in the upper layers, all of the hauls reaching from various 

 depths to the surface, with the exception of the haul at St. 2066, which is stated to be hauled from 

 1950 to 1550 m. Previous records, in which the depths are stated, indicate that the species belongs 

 to the upper layers. 



Remarks on the morphology. In contradistinction to P. martagon and laevis, this species is 

 mainly characterized by its long and narrow otoporpae and a continual increase in number of marginal 

 lappets and tentacles during the growth of the individuals. Its peripheral canals are decidedly 

 narrower than in the two other species, but broader than in P. nibiginosa. 



The shape of the umbrella is usually rather flattened, but occasionally it may be somewhat vaulted, 

 the gelatinous substance thick and moderately rigid, smooth; very young specimens are highly vaulted. 

 Gonads were seen only in some few of the specimens, and they were sac-shaped or half-moon- 

 shaped, simple or somewhat crenulated. When fully developed the marginal lappets are usually 

 tongue-shaped with evenly rounded external edge, rarely slightly pointed, a little longer than broad, 

 frequently one and a half times as long as broad; but owing to the continual addition of new lappets 

 by division of the older ones we almost always find some pairs of lappets of a particularly narrow 

 shape separated by a tentacle of smaller size than the others. Medium-sized specimens have about 

 21 lappets and tentacles, but the number may amount to 40, possibly even 48. In large specimens 

 with many tentacles the lappets are generally more elongated than in specimens with a smaller number. 

 The otoporpae are long and narrow, usually about as long as the lappets, but in young specimens 

 much longer. In fully developed lappets, their number is most frequently 3 or 5, the median one 

 slightly longer than the others, but sometimes there are 2 or 4. When a lappet with five otoporpae is 

 divided, the new peronium occupies the position of the median otoporpa, and each of the two new 

 lappets then has two otoporpae. Sometimes the otoporpae are mounted on slightly prominent 

 gelatinous keels, but these are never prolonged beyond the ends of the otoporpae. 



The peripheral canals (PI. VI, fig. 3) are of nearly the same width throughout their length, fairly 

 narrow, in fully developed lappets about one-eighth to one-sixth as broad as the lappet; in particularly 

 elongated lappets the canals are proportionately broader, but they never approach the remarkable 

 width as in P. laevis. 



