No. 385.] DEVELOPMENT OF ASTERIAS FALLIDA: 47 
gradually shrinks, and thus the metamorphosis is complete. . It 
is interesting to note that, according to Goto, the permanent 
cesophagus is fashioned out of the endodermal stump of the 
larval one. 
The fate of the ccelomic cavities next claims Dr. Goto’s atten- 
tion. Originally represented by two completely separated right 
and left sacs, these spaces have at the period of the first stage 
studied completely fused in the region of the przoral lobe. 
The left one is sharply constricted into anterior and posterior 
portions, and the right undergoes a similar constriction some- 
what later. In Asterina gibbosa, it will be remembered, there 
is not only constriction, but also complete separation into two 
parts in the case of both cavities. The left posterior coelom 
assumes a U-shaped form, sending out dorsal and ventral horns. 
A portion of the right posterior enteroccele is cut off from the 
rest and forms a closed sac, the “epigastric” coelom subse- 
quently occupying an aboral position in the young starfish. 
The remainder of the right posterior coelom fuses with the left 
posterior ccelom. The anterior coelom becomes completely cut 
off from the posterior coelomic sacs, and with the diminishing 
przoral lobe becomes largely obliterated, a portion persisting, 
however, as the axial sinus. In the septum dividing it from 
the left posterior ccelom, the stone canal is formed as a groove; 
this accordingly takes place long after the formation of the pore 
canal, 
Simultaneously with the diminution in size of the anterior 
cœlom, the watervascular rudiment, present from the first stage 
as a posterior swelling on the anterior coelom, becomes com- 
pletely separated from the axial sinus, the only communication 
remaining being that vza the stone canal. 
The axial sinus gives off a diverticulum, which forms the 
dorsal sac of Bury —a structure denominated by me the right 
hydroceele. According to Goto, it originates on the left side 
of the larva. 
A peculiar diverticulum of the left posterior coelom, mistaken 
by Ludwig (82) for a rudiment of the “heart,” gives rise to a 
space surrounding the adult oesophagus, and is named by Goto 
pericesophageal ccelom. It was called by me “oral coelom.”’ 
