592 



MEDUSA OF THE WORLD. 



GENERIC CHARACTERS. 



Cyaneidae with 8 marginal sense-organs and with 8 adradial clusters of marginal tentacles. 

 The tentacles of each cluster may arise in several rows from the subumbrella surface. There 

 are 8 chief lobes and 16 to 32 secondary lappets. Without radial-muscles in the lobes. 



Thenames Couthr,u\in andMedora are preoccupied, but Agassiz'sDesinvnt-mii may be used. 



The oldest species is the little-known "Chrysaora" gauJichaudii erroneously described 

 by Lesson, 1829 (Voyage de la Coquille, Zooph., p. 1 14), from the region of Cape Horn, South 

 America, and recently revealed through the studies of Maas, 1908. 



Some of the medusae which Haeckel included in his genus "Desmonema" represent only 

 immature Cyaneas in which the tentacles of each cluster arise in a single row. Vanhoffen, 1888, 



FIG. 376. Desmonema gaudichmtdii, after Maas, in Meduses Expedition Antarcticque Franc-aise. 



shows, however, that there are considerable anatomical differences between Cyanea in any 

 stage and Desmonema. In Desmonema, for example, the 8 clusters of tentacles arise in linear 

 arcs concentric with the general contour of the bell-margin, whereas in Cyanea they arise in 

 crescents, the horns of which are directed outward toward the margin. Moreover, there are 

 no radial-muscle strands in the 8 velar lobes of Desmonema, but these are found in Cyanea. 



Desmonema annasethc Haeckel is clearly a young Cyanea, as was pointed out by Van- 

 hofFen, 1888. 



The rediscovery of Lesson's, Cape Horn, medusa by Maas makes it practically certain 

 that it is specifically referred to by Agassiz, 1862, p. 118, under the designation Coiithouyia 

 pcndula. 



