INTROPrCTIOy. 
XIX 
specimen of ‘ Idmonea ’ mihieana, which he describes as having 
“the tip of the stem dilated for the formation of an ooecion”;^ 
whereas in the same paper he describes the ooecia of Entalopliora 
deflexa as similar to those of Crisia,~ and they are probably true 
goiicDcia, as in many fossil species of EntaJophora. 
MacGillivray ® also recognized that the ‘ooecia’ of his Tubuli- 
j»orid® were inflations of part of the zoarium and were not zooecial. 
This origin seems to me clearly established by Dr. Harmer’s work 
on the development of ‘ Lichenopora,^ for the term gonocyst was 
intended for the structures that Dr. Harmer^ describes as “a 
large compound ovicell.” He agrees with Smitt, and gives 
more convincing proof that these ovicells have been formed from 
interstitial, i.e. interzooecial, spaces; they are further enlarged, 
according to Dr. Harmer {op. cit. p. 91), by the absorption of 
“blister-like spaces” in the zoarium. As such ovicells are not 
homologous with those of Crisia, it seemed desirable to call them 
by a distinctive term, and ‘ gonocyst’ was therefore proposed.^ 
The original definition was intentionally indefinite as to the 
exact nature of these gonocysts, and ‘they were simply described 
as expansions within the zoarium, as that description would cover 
all indefinite cavities, whether formed by the fusion of several 
zooDcia, or from interzoa*cial spaces, or from both combined. 
Smitt’s observations on ' Lichoiopora' rerrucaria, as quoted above, 
with his record of eight openings from one ovicell and ray dissections 
of some Jurassic lierenicea, both supported the probability that 
gonocysts included both interzooecial and zooecial spaces. After 
the interzoa‘cial space is roofed over, it may expand laterally 
and possibly absorb the walls of the adjacent zooecia. Such 
liryozooites would be cut off from the surface and their existence 
> F. A. Smitt. “Floridan hryozoa,” pt. i. : Ilandl. k. Sv. Vet.-Akad. 
vol. X. Xo. 11, 1872, p. 19, pi. iii. fig. 16. 
2 Ibid. p. 12, pi. V. fig. 80. 
P. II. MacGillivray. “ A Monograph of the Tertiary Polyzoa of Victoria ” : 
Trans. 11. Soc, Viet. vol. iv. 1895, p. 129. 
^ S. F. Harmer. “On the Development oi Lichenopora verriicay'ia, Fabr.” : 
Quart. Journ. Micro. Sci. vol. xxxix. pp. 71-144, 1896 ; see p. 72. 
^ Dr. Harmer, to whom these paragraphs have been .shown at the request of 
the Author, considers that his paper “On the Development of Tubulipora 
(Quart. Journ. Micro. Sci. vol. xli. pp. 73-157, 1898) still precludes the 
acceptance of this view. 
