F. S. CONANT ON THE CUBOMEDUS^. 37 



Chiropsalmus, in which the peripheral edge of the larger marginal pocket 

 in each octant is not bow-shaped, but runs parallel to the edge of the 

 velarium. A revision of the terminology of the marginal pockets such 

 as implied in the suggestion above would also give rise to complications 

 when applied to Charybdea, since the latter has no marginal pockets in 

 the velarium. 



As to the functions of the vascular lamellae, there is too little known 

 to say much. It is rather improbable that structures retained so defi- 

 nitely should be mere scaffolding left over from a previous stage of 

 usefulness. Glaus has found in Chrysaora that the lamellae form a kind 

 of capillary network in communication with the gastro-vascular system, 

 and he with others supports the view that they perform an accessory 

 function in the nutrition of the tissues they penetrate. Upon this point 

 I have no observations of my own to add. 



The marginal vascular lamella is regarded by Glaus as perhaps the 

 vestige of a circular canal around the bell margin. On this subject, too, 

 I have nothing to add. A lamella of endoderm that connects directly 

 with the ectoderm of the surface along its whole course is a structure 

 whose meaning I am wholly unable to understand or even to guess at. 

 A similar lamella is described by Hesse ('95, p. 430) as occurring in the 

 ephyra lobes of his Rhizostoma, and he mentions Eimer as the first to 

 discover this structure, probably meaning the first to discover it in the 

 Discomedusa3. Whether the lamella is found all around the margin is 

 not stated. Hesse refers it to the ephyra, and remarks that the investi- 

 gation of it in the ephyra would undoubtedly give interesting results. 



I will close this part upon the vascular lamellae with a very pertinent 

 suggestion made by Professor Brooks to the effect that the usual way of 

 speaking of the sensory clubs as having moved up from the margin is 

 looking at the matter in the wrong way. The level of the sensory clubs 

 undoubtedly represents the original margin, which elsewhere has grown 

 down and away from its former level, leaving the sensory clubs like 

 floatage stranded at high-tide mark. Only in this way can the lamella 

 of the sensory niche have any meaning. 



B : THE NERVOUS SYSTEM. 



The nervous system of the Cubomedusas is the most highly devel- 

 oped that is found in any of the jelly-fishes. If the position of the group 

 among the Acraspeda is established, it alone is ample to prove that the 

 Hertwigs had not sufficient evidence when they stated in their mono- 



