44 
of young corallites quite uiitenahle.” The strongest point in tins reply seems 
to me to l)e tlie numerical preponderance of the acantliopores in some sections. 
Granting, for the sake of argument, that the acantliopores are the initial 
stages of new corallites — they would during growth towards maturity so 
entirely crowd-out and distort the corallites, already on their way to senility, 
as to leave traces of such an exceptional growth in some form or another. 
Xo section of a Stenopora, which has come under my notice, has presented 
any trace of such an inordinate growth of young corallites. 
In transverse sections young tubes may he distinguished usually 
nestling at the angles of the more mature corallites, similar in structure and 
appearance, but usually triangular, quadrangular (oblong or rhomboid), or 
pentagonal. They share with the older tubes the phenomena of thickened 
walls, and the presence of a secondary deposit within them. Much more 
rarely, young tubes appear as a portion of an older corallitc partitioned off by 
a more or less direct line. In those sj>ecies in which periodic growth is 
frequent and rapid, a large proportion of the newly-developed corallites do 
not appear to reach maturity. 
Heproduction in Stenopora takes place generally by intermural gem- 
mation, at rare intervals by fission. The young corallites mentioned above, 
in the first category, are the result of intermural gemmation, which consists 
in a subdivision or splitting of the primary wall of one or more corallites, 
and the gradual production therefrom of a similar tube. Young corallites 
which appear in a horizontal section as partitioned off from an old one are 
more probably the result ot fission. Eissiparity consists of a longitudinal and 
internal subdivision of a mature corallite, resulting in the production of two, 
at first within the space originally occupied by the one. Intermural gemma- 
tion can be studied with advantage in sections, and longitudinally-fractured 
examples of S. cr'mita, and S. ovaia, but more particularly the former 
(El. V, Eig. 2)b Eissiparity has been observed in a few instances also in 
S. crinita. 
The walls of Stenopora arc imperforate, as the researches of Messrs. 
"Waagen and Wentzel have conclusively shown. It will he remembered that 
the late Prof, de Koninck^ was the earliest Avriter to describe perforated Avails 
in Stenopora^, in a species he referred to S. ovata, Lonsdale, and, in consequence, 
• This figure has by inadvertence been reversed, giving to the new interpolated tube the appearance of 
proceeding downwards instead of upwards. 
^ Foss. I’al. Nouv. Galles du Sud., 1877, Ft. 3, p. 150, t. 7, f. 5 & 5a. 
3 De Koninck’s enlargement. Fig. 5a, certainly represents a Stenopora, but tlie determination of Fig. 5 is 
very questionable. It bears a much closer resemblance to Trachypora Wilkinsoni, mihi. 
