No. 385.] DEVELOPMENT OF ASTERIAS PALLIDA. 49 
to the backward displacement of the disk of the young starfish ; 
but I regard the coincidence between the sagittal plane of the 
larva and the vertical plane drawn through the madreporic pore 
_ and the mouth of the adult as an accidental agreement of no 
deep significance. The backward movement of the disk does 
not take place to anything like the same extent in Asterina 
gibbosa. It remains true there, in spite of Dr. Goto’s denial, 
that right to left in the larva is nearly dorsal to ventral in the 
adult. Sections orientated parallel to the frontal larval plane 
have given longitudinal sections of the stone canal which would 
be impossible were the relations of adult and larval planes such 
as described by Dr. Goto. 
With regard to the absence of the fixed stage, it is to be 
regretted that Dr. Goto has given us no information as to how 
he obtained his larva — whether they were reared from the 
egg, or whether they were obtained by the use of the tow net. 
Ludwig failed to find the fixed stage in Asterina gibbosa, prob- 
ably because the larvæ were not provided with a suitable sub- 
stratum ; and if Dr. Goto fished his metamorphosing larve out 
of the sea, it is quite conceivable that the time when fixation 
could occur was past, or that no suitable basis was provided for 
fixation. Glass is assuredly not such a substance; I never saw 
an Asterina larva fixed to glass; and it is surely not probable 
that the brachiolarian arms are developed for no purpose. 
I come now to what I regard as one of the most serious 
points of difference, namely, the meaning of the sac called by 
me the right hydroccele. In support of this position, I gave 
not only a clear account of its appearance unequivocally on the 
right side of the larva, but I also described a number of cases 
where exceptionally the sac had undergone further development, 
and produced lobes similar to those formed by the left hydro- 
ceele. Now, Goto has not seen the origin of the structure at 
all; this occurring at a stage considerably previous to any which 
he has figured, and his statements as to its later connection with 
the axial sinus are entirely due to the preservation of his larve. 
Many times in the earlier portion of my work was I tempted to 
make the same statement before I found out that corrosive sub- 
limate was unsuited for the preservation of these larve. 
