192 



CORYMORPHA. 



lighter tint ; the pigment-cells in the sensitive bulb (p, Figs. 320, 323) 

 are purplish-orange upon a light-yellow ground. When the Medusae 



move about, which they do with great rapidity, the tentacles are twisted 

 in knots, as stated above, but when at rest expand at right angles to 

 Fig. 323. the disk, and then the Medusa will often remain, bal- 



ancing itself upon its tentacles, perfectly motionless in 

 the water, appearing like a rosy tube, with its yellow 

 ring set in a rectangle of four brilliantly colored ocelli. 



Found at Naushon in September, the largest speci- 

 men being one fourth of an inch in diameter ; young 

 specimens have a shorter digestive trunk, and the rows 

 of lasso-cells extending along the outer surface of the 

 bell are more marked than in older specimens. The 

 Hydroid of this Medusa probably resembles the Tubularia Dumortierii 

 Van Beneden, the Medusa of which is closely allied to the one found 

 on our coast. 



Buzzard's Bay, Naushon (A. Agassiz). 



Cat. No. 441, Naushon, Mass., A. Agassiz. Medusa. 



CORYMORPHA Sars. 



Corymorpha Sars. Beskrlv., p. 6. 1835. 



Corymorpha Agass. Cont. Nat. Hist. U. S., IV. p. 343. 1862. 



Corymorpha pendula Agass. 



Corymorpha pendula Agass. Cont. Nat. Hist. U. S., IV. pp. 276, 343, PI. 26, Figs. 7-17. 



Corymorpha nutans Stimps. Mar. Inv. Grand Manan, p. 9. 1853. 



Corymorpha pendula A. Agass. ; in Proc. Bost. Soc. Nat. Hist., IX. p. 101, Pig. 31. 



The Medusa of Corymorpha is, like Hybocodon, asymmetrical ; the 

 shape of the bell is more elongated (Fig. 324) and the tentacles more 



Fig. 321. Fig. 320, seen from abactinal pole, to show tlie termination of tlie lasso threads. 

 Fin-. 322. Fig. 320, seen from the aotinal pole, showing the origin of the threads on each side 

 of the base of the tentacles. 



Fig. 323. The base of one of the tentacles, magnified, p, cluster of pigment-cells. 



