No. I.] THE SENSORY CLUBS. 289 



thirty-two solid accessory tentacles ; and in the radii of these 

 there are thirty-two marginal clubs, and close to the base of 

 each club there is a small ocellus, which is not on the club but 

 on the marginal ring. 



These marginal clubs are found in several species of ocellate 

 campanularian medusae, and they have been noted and figured 

 by A. Agassiz, and also by Haeckel who says that they are 

 probably organs of special sense. 



A. Agassiz gives a good figure of them in Phytogena lactea 

 {N. Amer. Acalephs, p. 138, Fig. 224), but only says of them in 

 this species that "between every two tentacles is found a club- 

 shaped appendage, made up of large cells somewhat like those 

 of Lafoea calcarata." His figure of them in this latter species, 

 which is a Laodice according to Haeckel's system, is very 

 obscure (Fig. 187). He says of them (p. 123): "We find still 

 a third kind of tentacle ; club-shaped appendages made up of 

 large polygonal cells, perfectly transparent, one or two some- 

 times placed between each of the larger tentacles." 



Haeckel, who proposes for them the name Cordyli, says 

 {System der Mediisen, p. 118): "Marginal clubs, or Cordyli, 

 are less frequent, on the whole, than cirri, and they may occur 

 together with or without cirri. I have, so far, found these 

 organs, which have been overlooked by most of the preceding 

 authors, only in ocellate Leptomedusae (Thaumantidae and 

 Cannotidae), while they are entirely absent in the vesiculate 

 Leptomedusae (Eucopidae and Aequoridae). Among the Thau- 

 mantidae they occur in Laodice, Melicertissa, and Melicertidium, 

 and among the Cannotidae in Staurodiscus, Ptychogena, Bere- 

 nice, and Toxorchis. They are numerous and are usually dis- 

 tributed irregularly between the tentacles and cirri. The 

 narrow stalk of the marginal club is always much smaller than 

 the enlarged rounded tip, which, in some cases at least, if not 

 in all, carries sensory cells with tactile bristles. They are 

 not, therefore, to be confused with the tentacular buds, which 

 have an enlarged base and a tapering tip. The cordyli are 

 probably organs of special sense, possibly substitutes for the 

 marginal vesicles, since they occur only in the Ocellatae and 

 are not found in the Vesiculatae." 



