542 MEDUS.E OF THE WORLD. 



of the Coronatae we would be inclined to regard Pericolpa as being only the young of Periphylla; 

 for the development of 8 adradial lappets and 8 corresponding tentacles would change the 

 medusa to Periphylla. 



The species founded by Haeckel are separated upon slight distinctions, some of which 

 represent mere stages in growth. Probably there are but two forms, P. quadrigata with an 

 elongate, pointed bell and P. camfana with a flat, dome-like bell; but even this can not now 

 be determined with any degree of certainty. 



This genus includes the simplest and possibly most primitive of the Periphyllidae. 



Pericolpa quadrigata Haeckel. 



Pericolpa quadrigata, HAECKEL, 1880, Syst.der Medusen, p. 41 3, taf. 23,fign. 1-12; P. galea, Ibid., p. 41 4; ( ?) P.terralina, p. 640. 

 MAAS, 1903, Scyphomedusen der Siboga Exped., Monog. II, p. 12. 



Bell 40 mm. high and 30 mm. wide. The pointed, dome-like apical half of the exumbrella 

 above the ring-furrow is as high as the width ot the pedal and lappet-zone below. The 4 

 perradial tentacular pedalia are somewhat wider than the 4 interradial, rhopalar ones and 

 somewhat longer than the 8 marginal lappets. The 4 tentacles are about as long as bell- 

 height. Throat-tube and stomach wide, rilling the greater part of bell-cavity. The basal 

 part of the stomach leads into the gastrovascular space of bell by 4 perradial ostia, which 

 are lined with gastral filaments. These ostia lead into a wide sinus which is interrupted by 

 4 short, partial septa in the interradii. Peripheral to these septa is another wide ring-sinus 

 which sends out 8 canals in the radii of the sense-organs and tentacles. These radiating canals 

 fork at their ends and extend around the edges of the lappets, forming a marginal ring-canal. 

 The 8 gonads are grouped in 4 pairs on either sides of the interradii. Their inner ends are 

 close together but they diverge outwardly. Color ( ?) 



Found in the Antarctic, southeast of Kerguelen Island by the Challenger, and apparently 

 identical with P. galia from the east coast of Australia. 



Pericolpa campana Maas. 



Pericrvpta campana, HAECKEL, 1880, Syst. der Medusen, p. 414. 



Pericolpa campana, MAAS, 1903, Scyphomedusen der Siboga Expedition, Monog. n, p. 13, taf. 3, fign. 19-22. 



Bell about 15 mm. high and 15 mm. wide, with thick gelatinous walls. A deep ring- 

 furrow around exumbrella separates the evenly rounded dome-like center of bell from marginal 

 zone of lappets. The 8 clefts between the 8 pedalia are also very deep. The 4 tentacular 

 pedalia are nearly similar in size to the 4 pedalia of the sense-organs. The 4 tentacles are 

 tapering and shorter than bell-radius. They are solid and their axial cores project into the 

 gelatinous substance. These tentacles are situated in the perradii. Each of the 4 interradial 

 marginal sense-clubs contains a terminal entodermal concretion and a ventral bulbular 

 swelling, but no ocellus. The 8 marginal lappets are semicircular. 



Stomach wide at base, and there are 4 interradial clusters, each with at least 30 gastric 

 cirri. The stomach is connected with the gastrovascular space of the bell by 4 perradial 

 openings. Peripheral to these there is a wide ring-sinus and this in turn gives rise to 8 radiating 

 canals in the radii of the tentacles and sense-organs, and these fork and communicate one 

 with another at their outer ends, forming a marginal ring-canal. The circular muscles of the 

 subumbrella are well developed and there are radial-muscle strands near the bases of the 

 tentacles. There appear to be 8 gonads. Maas records 7 of them irregularly arranged in a 

 zone at middle of subumbrella, and Haeckel's specimen was so poorly preserved that he does 

 not record the character of the gonads. Color (?) 



Haeckel's specimen came from the region of New Zealand, while Maas records one from 

 the Malay Archipelago, where it was obtained in a vertical net hauled from a depth of 500 

 fathoms in 17.6' S. lat., 129 14.5' E. long. 



This medusa is distinguished by its oval gonads. 



Pericolpa tetralina Haeckel. 



Perieolpa ietralina, HAECKEL, 1880, Syst. der Medusen, p. 640. 



This medusa is probably identical with P. quadrigata, but both ends of the 8 gonads 

 diverge from the 4 interradii, while in P. quadrigata only the outer ends diverge and the inner 



