78 — Mr. Gnirrrrn on the Development of 
albumina which are developed in the tissue of the amnios and inclosed in an 
ordinary integument or integuments, with this obvious difference, that in the 
subjects under consideration this body is naked. 
There is an evident resemblance between the nipple-shaped process of vis- 
cum, and the often stipitate, free, central placenta of Santalaceæ, especially 
when more than one embryo is developed in the above genus *. 
On the Mode of Parasitism. 
The only species in which this has been studied in any detail is the Viscum 
album, and even here the statements are not altogether satisfactory. The 
latest account which I have seen is that of De Candolle in his excellent Phy- 
siologie Végétale, vol. ii. p. 790, and more fully in vol. iii. p. 1409, where the 
subject is treated in the usually luminous manner, so characteristic of this 
distinguished author. 
The mature seeds of all the species of Loranthus adhere strongly to the 
substance on which they are applied by means of the viscous matter, This 
viscum soon hardens, and then has the appearance of a transparent glue. The 
first changes take place in L. Scurrula two or three days after application, 
and consist of a curvature of the extremity of the radicle towards the sup- 
port; this extremity when it reaches this point becoming enlarged and flat- 
tened 1. 
It has now the appearance of a sucker, such as those, for instance, of the 
Cassytha filiformis. 1 am unable to state the precise manner in which the 
radicle penetrates the bark. The operation seems to require some time, and 
it is not until it is completed that the plumula begins to be developed. In 
those species the cotyledons of which are soldered together, the plumula 
passes out by one of the clefts; in the others by the fissure between these 
two bodies. The cotyledons in all the species I have examined remain in- 
closed in the albumen, which substance begins to disappear as soon as the 
plumula commences to be developed; the cotyledons undergoing a corre- 
* Compare the figures 2 and 3 of Viscum with that of the placenta of Thesium linophyllum. Bron- 
gniart Sur la Génération des Végétauz, Plate 43, fig. 3. B & C. 
T See Tab. VII. fig. 1, 2, 3, 4& 5. 
