232 W. WOODLAND. 
hope to publish, from time to time, papers containing the 
results of my inquiries in this direction. Whilst so engaged 
in elucidating the facts I may, on occasion, be tempted to 
accompany them with interpretations, but, however this may 
be, I propose to more fully deal with the theoretical aspect of 
the subject at the close of the series of studies contemplated, 
ensuring by this procedure a sound basis of facts upon which 
to found my final conclusions. 
The present paper on Sycon spicules—forming the first of 
the series—was concluded long before I had decided to ex- 
tend my researches to other groups, and in consequence the 
Theoretical Considerations forming Part IT are to be received 
with caution. I retain these speculations because, crude as 
they may ultimately turn out to be, I am firmly convinced, 
judging from my later researches, that they contain a large 
element of truth. 
Part I. Description of Spicule Formation in Sycons. 
INTRODUCTORY. 
An account of the development of the spicules in Homo- 
coelous Calcarea (Ascons) having been published in January, 
1898, a parallel inquiry into the conditions obtaining in the 
Heterocceela (Sycons) is desirable in order to establish the 
mode or modes of formation of these skeletal structures for the 
Calcarea as a whole. This is more especially necessary since 
Dr. O. Maas” has recently attempted to describe the develop- 
ment of the Sycon spicules, and in so doing has unfortunately 
presented a very erroneous view of the facts.’ For these 
reasons then, and at the suggestion of Prof. Minchin, I under- 
1 B®. A. Minchin, “‘ Materials for a Monograph of the Ascons,” I, ‘ Quart. 
Journ. Micr. Sci.,’ vol. xl. 
2 « Die Weiterentwicklung der Syconen,” in ‘ Zeit. fiir wiss. Zool.,’ xvii, 2, 
1900. 
3 Since Maas’ statements and figures have already been incorporated in 
the text-books (e. g. Haller’s), it is still more essential that these erroneous 
views should be combatted. 
