OF MKDUS.K MA11F, BY WILLIAM KEITH BKooKS. 



15 



Genus PERSA McCrady, 1857. 

 Persa incolorata McCrady. 



Pena incolorata, MCCRADY, 1857, Gymn. Charleston Harbor, p. 104, plate 12, fig. 3. AGASSIZ, A., 1865, North Amer. Acal., 

 p. 50. HAECKEL, 1879, Syst. der Meduscn, p. 279. 



Bell oval and about 3 mm. in height and 1.5 mm. in diameter; walls thin. There area 

 large number of long, brittle, club-shaped, ciliated tentacles. 8 sensory-clubs between the 8 

 radial tubes. Velum large and muscular. 8 very narrow, straight radial tubes and a slender 

 circular vessel. Peduncle short and conical. Stomach cylindrical, about half as long as bell- 

 height, with 4 long cruciform lips. The 2 gonads are developed on 2 diametrically opposed radial 

 tubes. They arise from these tubes upon the subumbrella and project inward into the 

 bell-cavity. 



FIG. 261. Persa incolorata, young medusa, from Beaufort, North Carolina. 

 FIG. 262. Persa incolorata, mature medusa, from Beaufort, North Carolina. 

 Drawn from life, by Prof. W. K. Brooks. 



