210 Parkin.—Observations on 
together on a small scale of the articulate and inarticulate 
types. 
No such laticiferous tissue is developed in the young seed 
of the somewhat closely allied rubber-tree, Mariihot Glaziovii. 
The developing seeds of three other members of the order 
have been examined, viz. Croton tiglium , Jatropha multifida 
and Euphorbia Lathyris , without finding any such system. 
It will be instructive to extend the investigation to other 
genera of the laticiferous Euphorbiaceae, to ascertain whether 
any more cases like that of Hevea are to be found, likewise 
to see whether this laticiferous system of the seed-coat of 
Hevea may be considered as a new production or as vestigial 
in the evolution of the group, as well as to endeavour to 
discover what function, if any, it may perform here. 
This laticiferous system just described is interesting from 
another point of view. Scott 1 , who has investigated the 
laticiferous tissue of the vegetative parts of Hevea brasiliensis 
and Manihot Glaziovii , showed that the tubes are true 
vessels, formed by the breaking down of the septa of rows 
of cells, and that these do not give out conspicuous pro¬ 
cesses. On the other hand, in the young seed of this 
plant, it has just been pointed out that the processes or un¬ 
segmented outgrowths from the cells are an important item 
in the construction of this laticiferous system. 
Remarks on the Origin and Function of 
Laticiferous Tissue. 
The morphology of the laticiferous tissue of the Euphor¬ 
biaceae is of much interest. When De Bary published his 
Comparative Anatomy of the Phanerogams and Ferns, the 
Euphorbiaceae were considered as including only plants with 
the inarticulate type of laticiferous tube. 
Scott 2 in 1884 and 1885 showed that Manihot and Hevea , 
members of this order, had, however, an articulate laticiferous 
1 Scott, Quart. Tour. Micro. Soc., Vol. xxiv, 1884, and Jour. Linn. Soc., Vol. xxi, 
1885. 2 Sc ott, loc . cit 
