No. 2.] DEVELOPMENT OF MANICINA AREOLATA. 235 
which the Anthozoa are descended from hydropolyps with gas- 
tric ridges. This hypothesis, which considers the distinguishing 
feature of the Anthozoa (and Scyphomedusz) to be the posses- 
sion of taenioles, or endodermal ridges (mesenteric ridges), has 
recently been attacked by Professor Gotte in a very interesting 
paper (17) on the development of the Scyphomedusze (Aurelia). 
The author conclusively proves the Anthozoan nature of the 
Scyphostoma larva, showing it to possess four complete mesen- 
teries and an ectodermal cesophagus. Unfortunately, no obser- 
vations were made on the origin of the mesenterial filaments, 
which in all probability are ectodermal lobes. Regarding, then, 
the Scyphomedusz as an offshoot from the older Anthozoan 
Fig. b 
Ectoderm represented as made of columnar cells. Endoderm is dotted. Support- 
ing lamella left untouched. After Gédtte, Pl. II., Figs. 20 and 24. 
stem, Gotte argues that the manner in which the mesenteries 
and intermesenterial chambers are formed in the larva of the 
former, is directly opposed to the old view of the hydroid origin 
of the Anthozoa. The mesenteries and chambers are formed in 
the following manner: the planula is bilateral, and the perma- 
nent layers are formed before the invagination of the cesophagus 
takes place. The latter is invaginated in such a shape that in 
the shorter transverse axis of the larva the endoderm is pushed 
down, while in the other transverse axis two endoderm sacs are 
formed. The woodcut, Fig. 1, is a transverse section of this 
stage, through the cesophagus, and Fig. 2 is a longitudinal section 
through the shorter transverse axis. In a subsequent stage, 
