302 MR. W. GRIFFITH ON THE GENUS GNETUM. 



must likewise advert to this period when they state the nucleus to be surrounded with 

 three envelopes. 



The nuclevis, which up to the present time continues free from adhesion, has now 

 undergone a slight alteration in figure, consisting in a tendency to constriction towards 

 its apex, which is now invariably more or less brown : its cavity has become enlarged. 

 This constriction may possibly be only apparent, since it may originate in the greater 

 growth of the elevated part of the depression, stated to exist at the apex. 



As the young seed progresses in its development, the two outer coats increase in size. 

 The base of the additional membrane adheres to the corresponding portion of the nucleus, 

 the adhesion continuing to increase in extent until it has reached upwards to the com- 

 mencement of the constriction. The projecting tubular prolongation does not appear to 

 have any regular term of existence; its coloration or sphacelation increases, and at a 

 vai'iable period the exserted portion becomes detached at the situation of the opening of 

 the outer coat. The cavity existing in the nucleus undergoes a corresponding enlarge- 

 ment, and its walls are more irregular. It wUl be found to contain, about the period of 

 detachment of the exserted portion of the tubular process, a pendulous body of a similar 

 form, attached by a rather broad cellular band to the apex of the cavity. This is the 

 rudimentary amnios, developed originally within the sac, stated to line at a prior period 

 the cavity of the nucleus. As the development proceeds, this body increases in size; it 

 appears to be developed from below upwards, and as it enlarges, the lax cellular attach- 

 ment undergoes a corresponding diminution, chiefly, I imagine, by pressure. As this 

 body, in which the albumen becomes deposited, increases, the substance of the nucleus 

 gradually disappears, and subsequently merely forms a thin covering to the large and 

 fleshy albumen. The last change which I have traced in the albumen consists in the for- 

 mation of a cavity within its substance, commencing at its apex, and gradually extending 

 downwards. The corresponding changes consist in the development of pulp and increase 

 of the fibres of the outer coat ; in an induration (rather in an induration of the second 

 envelope depending upon the development of fibrous tissue) and development of fibrous 

 tissue in the second envelope, which svibsequently becomes brown, subosseous, and fragile. 

 The originally large and distinct operdngs through both these become narrowed, but never 

 completely filled up— not, at least, by an extension of then- own substance. The additional 

 envelope is now membranous and thin, united throughout the greater part .of its extent 

 to the thin remains of the nucleus. The included (and permanent) portion of its origin- 

 ally tubular prolongation has become filled up, and is embraced closely within the con- 

 stricted openings existing through the two outer coats. The remains of the nucleus, 

 owing to the pressure this has undergone during the growth of the albumen (or rather of 

 the amnios and deposition of albumen), finally assume the form of a membrane, united, 

 except towards its apex, which is brown or black and apiculate, to the inner paries of the 

 third coat. 



With regard to the development of the embryo, I can add nothing. Although I have 

 examined abundance of fully-formed fruits of two species, I have never observed anything 

 towards the development of the embryo beyond the formation of the cavity in the 

 albumen, and the very rare and partial development of the funiculus, which, moreover, in 



