CASSIOPEA XAMACIIANA. 211 



ward the ectoderm is pushed out until the principal radii) e-e and f-f, Fig. G) gradually 

 become equal. This results in the formation of the flattened peristomal disc (Figs. E 

 and F) . At the same time the wall separating the oesophagus from the first pair of gastric 

 pouches (Taschenvorhang) is split upward until the openings into the two pairs of pouches 

 are upon the same level, and the " Taschenvorhang " is reduced to a low ridge, while the 

 oesophagus is very much shortened. Portions of the original lining of the lower part of 

 the oesophagus persist as the covering of the inner edges of the septa which separate the 

 four gastric pouches. The larva is now in what Goette calls the scyphula stage. He 

 regards this stage as of great phylogenetic importance, showing clearly, he thinks, a 

 close genetic connection between the Scyphomedusae and the Anthozoa ; so that these 

 groups should be placed in a single class, Scyphozoa, to distinguish them, on the one 

 hand, from the Hydrozoa, including the hydroids, hydromedusae, and, on the other, from 

 the Siphonophorae. 



This view, which is confirmed by Miss Hyde, is antagonized by Glaus, and has given 

 rise to a prolonged controversy. The parties to this dispute are practically in accord 

 in regard to the facts of observation, as represented by the figures in their latest 

 contributions. It is in the interpretation of these facts that they differ mainly. Clans 

 f 90) admits that there is an ectodermal invagination previous to the formation of the 

 mouth, and that the lining of the proboscis is ectodermal. He maintains, however, that 

 the condition represented in Figs. B, C, and D, is due to a severe contraction of the 

 animal, and is without morphological significance. He denies that there is any 

 oesophagus, " Taschenvorhang," or " Schlundpforte," in the sense that Goette uses these 

 terms ; and with these he rejects the idea of a close affinity between the Anthozoa and 

 scyphomedusae, with the correspondingly sharp distinction between the latter and the 

 hydromedusae. He admits, however, that a distinction of importance between scyphis- 

 tonia and hydropolyp is to be found in the possession by the former of an ectodermal 

 lining of the proboscis, and in the presence of gastric pouches and septa. 



Goette's position has been strengthened considerably by his latest contribution on 

 this subject ('93), and his conclusions are confirmed in nearly every particular by Miss 

 Hyde. Goette's figures appear to be camera drawings of serial sections, and are a 

 great improvement over the rather diagrammatic illustrations in his earlier papers. 

 They are not entirely convincing, however, for the ectoderm and the endoderm grade 

 into each other so that it is impossible to determine the exact boundary ; and the 

 material is so subject to distortion during the preservation that it is often difficult to 

 determine whether a given fold of the epithelium is of morphological value or is merely 

 an artifact. 



Miss Hyde fails to confirm the view that the whole of the second pair of gastric 



