616 



MEDUSA OF THK WOliLl). 



vessels. The ring-canal gives rise centripetally to a shoit diverticuliini in the radius of each 

 sense-organ and to 8Xi6 inter-rhopalar diverticula. The gonads are 4 inrerradial, sac-like, 

 protruding pouches separated by narrow intervals in the perradii. 



This species is closely related to P. sicula of the Mediterranean and Pacific, hut is dis- 

 tinguished by having 32 instead of 16 velar lappets. It is found along the Pacific coast of 

 North America, Port Townsend and Straits of Kuca, Washington. 



Phacellophora ornata Haeckel. 



Callinema ornu/a, VrRRiLi., 1869, .American Journ. Sci., scr. J, vol. 48, p. 117; .Ann. and Mag. Nat. Hist., vol. 4, p. 161. — KewKts, 



1888, Bull. Mus. Comp. Zool. at Harvard College, vol. 13, No. 7, p. 135, plate 5, 4 figs.; 1888, Report U. S. Expedition to 



Lady Franklin Bay, vol. 2, p. 40. 

 Phacellophora ornata, Hakckki., 1S80, Syst.der Mciluscn, p. 643. — Hargitt, 1904, Bull. U.S. Bureau of Fisheries, vol. 24, p. 68. — 



VANHorrcN, 1906, Nordischcs Plankton, Nr. 11, p. <;9, fign. 25-26. — Browne, 1908, Trans. Royal Soc. Edinburgh, vol.46, 



p. 247, plate 2, figs. 3, 4. 



Disk quite flat, with a slight dome-shaped ahoral apex; it is about 350 mm. in diameter, 

 and the marginal lappets droop vertical!)'. The surface of the e.\umbrella is covered with 



small nematocyst-warts. Gelati- 

 nous substance of disk quite thick 

 and rigid. 16 marginal sense- 

 organs are set within niches be- 

 tween the 32 ocular lappets. 

 Ocular lappets about twice as long 

 as velar ones, but not so numerous, 

 there being 2 to 4 velar between 

 each successive pair of ocular lap- 

 pets. The clefts separating the 

 ocular lappets are deeper and 

 more distinct than those separat- 

 ing the velar lappets. Over 100 

 long tentacles arise from the floor 

 of the subumbrella in a broken 

 circle in 16 inter-rhopalar clusters 

 at a short distance inward from 

 the bases of the marginal lappets. 

 The 5 to 9 tentacles between each 

 successive pair of sense-organs 

 vary considerably in size, the long- 

 est being about equal to bell- 

 diameter; the\ are hollow and flat, 

 and there is a wavy double thick- 

 ening along the centripetal narrow 

 edge, which is covered with nema- 

 tocysts. Mouth simple and 4- 

 cornered, situated at center of 

 subumbrella. The 4 mouth-arms 

 are each about as long as bell- 

 diameter, their free edges much 

 folded. They are highly flexible 

 and contractile. The gonads are lound 111 4 inierradial, crumpled sacs which project out- 

 ward troiTi the floor of the subumbrella at the sides of the mouth. Central stomach 4-lobed, 

 being extended outward in the radii of the 4 genital organs, verv much as is the case in 

 AurAlia. .\ large number of radiating canals run outward from the periphery of the central 

 stomach to the circular canal, which lies at a considerable distance inward from bell-margin. 

 1 he radiating canals in the radii of the sense-organs branch and anastomose, while those in 

 the tentacular radii are simple and slender. There are about 2 to 5 of these simple canals 

 between each successive pair of anastomosing canals. Circular canal broad, somewhat sinuous, 

 and it lies under the insertions of the ring of tentacles. Outwardly it gives rise to a blind canal 



Pharellophora ornnra. 



