422 



MEDUSAE OF THE WORLD. 



Umbrella bell-shaped, about 1.5 times as broad as high, about 15 mm. in diameter, the 

 sides flanged. There are 4 long, hollow, radially situated tentacles covered with rings of 

 nematocysts. These radial tentacles are very flexible and two or three times as long as diameter 

 of umbrella. There are also 4 short, stiff, solid, interradial tentacles that are curled sharply 

 upward. These small tentacles are armed with groups of nematocyst-cells upon their outer 

 (peripheral) sides. These small tentacles are easily broken off and are occasionally wanting in 

 mature individuals. There are 8 lithocysts, each containing a single, spherical concretion. 

 4 of these are situated near the bases of the radial tentacles and 4 at bases of the interradial ten- 

 tacles. Velum well developed. The circular canal has not more than one short interradial 



Fig. 278. — Liriope scutigera, after Brooks, in Mem. Boston Soc. Nat. Hist., 1886. 



diverticulum in each quadrant. There are 4 radial tubes, upon which the 4 gonads are 

 developed. Gonads, nearly square to circular with rounded corners, extend from near the 

 circular vessel to inner apex of subumbrella; in old individuals they nearly meet along the 

 interradii. Peduncle thick and conical above, slender and prismatic below, usually a little 

 longer than diameter of bell. Mouth quadrate, with a tongue-like, gelatinous process within 

 gastric portion that may sometimes be protruded beyond the mouth. 



The body of the medusa is so very hyaline that it is difficult to discover its presence in the 

 water. The lips are often of a delicate emerald-green and their nematocyst-cells are tinged 

 with a delicate purple. 



