614 



MEDUS/E OF THE WORLD. 



ently under the impression that it was identical with P. ornata Brandt, from the Pacific, but 

 Haeckel rightly distinguished it as a distinct species. 



The following description is based upon my study of a single good specimen of this medusa 

 collected by Dr. S. Lobianco at Naples, Italy, on January 1 1, 1901, and now preserved in 

 formalin at the Naples Zoological Station. 



Disk 155 mm. in diameter, flatter than a hemisphere, being only 55 mm. high. Exum- 

 brella surface finely granular, being covered with small, thickly clustered nematocyst-warts. 

 1 6 marginal sense-organs, 4 perradial, 4 mterradial, and 8 adradial. Sense-organs set at 

 bottom of deep, narrow clefts in bell-margin. The sense-club has no ocellus, merely a terminal 

 mass of entodermal concretions. No sensory pit in exumbrella above the sense-club. 32 

 narrow, rhopalar lappets are separated by shallow clefts from the 16 wide, velar, simple lappets. 



FIG. 391. Phacellofhora sicula, drawn by the author, from a specimen found at Naples by 

 Dr. S. Lobianco, January II, 1901. B, enlarged view of part of one of the tentacles. 



The tentacles are arranged in 16 clusters and arise in a single row from the inwardly- 

 arched outer margin of the ring-canal, on the subumbrella side of the 16 velar lappets. Each 

 cluster consists of about 9 to 15 tentacles. In the Naples specimen these tentacles are about 

 half (75 mm.) as long as diameter of disk and are set inward at a maximum distance of 17.5 

 mm. from the bell-margin. A narrow canal extends throughout the length of each tentacle 

 on the inner (centripetal) side to its tip. A double row of mammiform, nematocyst-bearing 

 papilla; extends along the inner side of each tentacle close to the tentacular canal, which sends 

 off lateral diverticula into the papillae. The outer (centrifugal) side of each tentacle is pro- 

 vided with circular muscle-fibers, which are interrupted along the line of the papillae. 



