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cauline collar-like narrowing. This projection has been found in 
A. Tilesi, A. melo, A. costata, A. junipérus, A. Jilicula, Å: coei, 
(Pl. IV, fig. 22), A. gracilis and in those forms which Kirchen- 
pauer has designated as A. abietina, var. minor, A, abietina, var. 
purpurea and 4. filicula, var. tornata. 
In 4. Traski the diaphragm is on each side provided with a 
triangular, pointed, ascending portion. 
Thujaria salicornia AHman,”) which, as far as I know, has 
not been mentioned since it was deseribed, is identical with Serr. 
fusca Johnst., and the reason why this fact has not been earlier 
detected "is, no doubt, that the hydrothecae look very different in 
the figures given by Hincks and in those given by Allman. 
The pinna figured by Hincks is namely seen from one of the 
broad sides, while the two pinnae figured by Allman are seen 
from one of the narrow sides. 
Broch regards Diphasia pulchra Nutt. as a synonym to 
Thuj. thujarioidées (Clark), and the two forms, which have quite 
similar gonothecae, are no doubt nearly related, but a comparison 
between specimens of both lias led me to the result, that they must 
be regarded as distinct species. I shall here only point out that 
in 4. pulchra the very short free distal portion of the hydrothecae, 
which is provided with an adcauline collar-like narrowing, is only 
by a very narrow interspace divided from the adjacent portion of 
the branch, while in A. thujarioides the much longer distal portion 
has no narrowing and is divided from the stem by a rather broad 
and deep sinus. ; 
The abcauline wall of Diph. digitalis (Busk) presents a feebly 
developed membranous collar, and, therefore, the aperture is pro- 
vided with two feeble lateral teeth. 
Sertularella (Gray) Hineks. | 
The aperture is provided with 3—4 marginal teeth, between 
which are found as many curves. In each curve is fixed an oper- 
cular membrane provided with a large free, valvular portion. 
y I, P- 
