Miscellaneous. 
171 
and the nervures were enclosed between the two epidermal laminae; 
but the leaves are especially distinguished by the extreme abun¬ 
dance of gummous ducts. These ducts, of which the true structure 
is not yet determined, accompany and surround the vascular bun¬ 
dles ; in many cases these organs carbonized form filaments substi¬ 
tuted, so to speak, for the true nervures, which they conceal while 
indicating their direction. This character occurs, though in a less 
degree, in the leaves of the Corda'iteae. 
The leaves of the Dolerophylleae must have produced on the stems 
which bore them rounded or transversely ellipsoidal insertion-scars. 
Such scars occur on the surface of many of the stems hitherto placed 
under the Calamodendreae, and tho leaves of which are unknown. 
The reproductive organs, discovered by M. Renault and ascribed 
by him to the Dolerophylleae, are very singular at the first glance; 
but while they depart from what we are accustomed to see in the 
Phanerogamia, they attest the existence of a category of plants in 
which fecundation took place by the agency of corpuscles differing 
but little, notwithstanding their considerable dimensions and com¬ 
plicated structure, from the grains of pollen observed in the micro- 
pyle or in the pollinic chamber of several Palaeozoic Gymnosperms. 
Thus the Dolerophylleae will represent, in the midst of a primitive 
vegetation, in which the Cryptogamia formerly appeared to have an 
uncontested predominance, an additional phanerogamic element, 
without any direct relationship to the existing Gymnosperms. But 
the distant alliance of the Dolerophylleae with the Corda'iteae, and 
the relations of the latter to the Cycadeae, recently demonstrated 
by M. Renault, show clearly that in the Carboniferous epoch the 
Dolerophylleae were related to a whole series of prototypic phane¬ 
rogams, of which the Sigillarieae must also have formed part.— 
Comptes Rendus, September 9, 1878, p. 393. 
Oh the Development of the Chilostomatous Bryozoa. 
By M. J. Baiirois. 
1. Formation of the Larva. —A. After the stage 32 (blastema 
we may distinguish in the ovum four series of cells, viz. :—1. Foui 
central cells of the inferior surface (these are covered by the peri¬ 
pheral cells, and penetrate into the interior to form the endoderm); 
2. Twelve peripherals of the inferior surface, which undergo seg¬ 
mentation transversely to form the oral surface; 3. Eight peri¬ 
pherals of the upper surface, which are segmented longitudinally to 
form the crown; 4. Eight centrals of the upper surface, which are 
segmented transversely to form the aboral surface. 
B. The four endodermic cells increase rapidly, and soon separate 
into two distinct parts :—1, a full central mass with its cells irre- 
gularly arranged; 2, two peripheral series of large regular cells. The 
former appears to represent the internal lamella; the second the 
mesoderm. 
C. The internal lamella changes into a voluminous mass of nutri¬ 
tive vitellus, which fills the embryo, whilst the series of mesodermic 
cells diminish until they become almost invisible. 
