Volume 1, Issue 10
April 1935, pages 571-675
pp 571-578 April 1935
The Golgi elements lying below the zona enlarge on fertilization.
The rims of the fatty yolk droplets break up into irregular granules, the majority of which also form a concentration below the zona radiata.
Concurrent with these changes the inner portions of the zona become converted into a mucilaginous envelope with an outer definite membrane.
When the mucous envelope is completely formed, the majority of the Golgi are extruded.
The function of the Golgi in Oogenesis is only secretory, the nature of the secretion being only secondary in importance.
pp 579-585 April 1935
pp 586-606 April 1935
pp 607-632 April 1935
pp 633-639 April 1935
The present paper comprises firstly a brief review of all the known Dipterocarpoxyla described since 1916 when Miss Holden instituted this genus. The more important anatomical characters of all the species have been summarised in the form of a table. But the original speciesD. burmense and a few others have been omitted because their affinities with the Dipterocarps are open to serious doubt.
Secondly, a new species ofDipterocarpoxyloi (D. Holdeni) has been described from the Irrawady system (mio-pliocene) of Burma. The poor preservation of this species has prevented further comparison with the timbers of the living Dipterocarpaceæ, but the close resemblance with the wood ofShorea robusta brought out in the present paper amply justifies the reference of this wood to the “Sal” family.
pp 640-649 April 1935
The early development of the anther is of the usual type. The parietal tissue is composed of an endothecium, two to three middle layers and the tapetum. The tapetal nuclei divide mitotically and as many as eight nuclei are produced in each cell, even before the mother cells have gone through the reduction divisions.
The four microspores may be arranged either tetrahedrally or isobilaterally. The mature pollen grain is two-nucleate.
There is usually a group of sporogenous cells in the young ovule, but only one functions and becomes the megaspore mother cell. A primary wall cell is usually cut off, but the nucellar epidermis also divides and takes part in the formation of a massive nucellus.
There is a linear tetrad of four megaspores, of which the chalazal functions and undergoes the three successive divisions to produce a normal eight-nucleate embryo sac. The synergids are ephemeral, while the antipodal cells are very conspicuous and persistent.
It is concluded that theBerberidaceœ shows a close relationship with theRanunculaceœ and both should be included in the same order.
pp 650-675 April 1935
The structure and themodus operandi of the gastric armature ofSquilla nepa, Latreille, is described with special reference to the development of its external masticatory appendages.
The formation of the gastric armature in the larval and the early adult stages ofSquilla nepa, Latreille, is described.
It is shown that the nature of the evolution of the gastric armature in Decapoda is determined by—
the nature of the food of the animal;
the nature of the external masticatory developments;
the nature of the environment, habits and habitats of the animal;
the nature of the mechanism of digestion and absorption in the animal; and
to some extent by the generic evolution of the various groups.
It is indicated that the sum of the external and internal masticatory efficiency is approximately constant.
The trend of the evolution of the gastric armature in Decapoda is traced.