SEED-STRUCIURE OF RAFFLESIACE AND HYDNORACER. « 311 
cases different from those overlying it, in consequence of the cells 
being narrower; but the degree of difference is variable. Moreover, 
it could not be ascertained whether this layer consists of four cells, as 
in the others, or whether it remains 2-celled. This must be considered 
in the light of embryo-bearer, or connecting channel. Again, we must 
not omit mentioning that the data upon which the explanations ‘Nats 
i verified b 
» fro 
union of all the cells, their universally equal size and similarity of 
co yee we might, reasoning from cause to effect, just as readily have 
taken the whole mass contained within the seed as an exalbuminous 
siSeyo, with an early and marked separation of the dermatogen. 
In Pilostyles* ‘the seeds (fig. 7) are sessile on the smooth inner 
surface of the fruit. They are also provided with a very hard and a 
more or less deeply brown coloured testa, with, however, an outer 
covering consisting of a thin layer of tender-walled juicy cells. The 
ovul w originate are anatropous, and 
furnished with two coats (fig. 8), ch, however, the out very 
fruit with a serve well t ares a view that seeks to destroy 
the marked difference between the atropous ovules of Rafflesia and the 
anatropous ones of Pilostyles, inasmuch as the rudimentary outer coat 
in the latter genus would be looked upon as of the same nature as the 
chalazal swellin ing in Raflesia. It is evident that in the ripe seed the 
siinee Shane t to discern the bou ne of the ¢ 
Now this testa is composed of a single 4 in ies only, of a 
double 1. layer of cells, which soon become very intimately united, and 
Whose brown membrane is pierced with numerous pore-channels. T 
breadth, shape, and frequency of the latter, and the relative thick- 
hess of the cell- dae od diameter of the sett: cavity varies in all the 
Species ex amined ; at the species might be determined from the 
Smallest fragmen t of ie seed-skin. The thickest and most homo- 
geneous partitions—and hence the greatest density—is found in the 
dark reddish-brown testa of P. Inga, and the thinnest cell-walls and 
Pat cavities are peculiar to the straw-coloured testa of 
The contents of the hard, granular embryo-sac membrane consist 
TD aieperce ye ee a 
Th ju2m indebted to the kindness of Dr. Asa Gray for ripe fruit of P. 
Batt, A. Gray ; and from Prof. Haussknecht, I had fruit of P, Haussknechtii, 
Olss. forthermors, I received bie fruit- bearing s specimens of Sarna Inge, 
amongst the m — sent to me, with their usual liberality, from the 
5 
