OEGANOGKAPHY. 
49 
Free veins are — 
Simple when each vein proceeds from the costa to the margin 
without branching (83). 
Forked when they divide at an acute angle into two or more 
branches after leaving the costa (51). 
Simply forked, or dichotomous, when the division is into two 
branches (96). 
P innately forked when the primary veins are scarcely defined, and 
branch several times one after the other on both sides (75). 
Pinnate when the primary veins that run from the costa to the 
margin are distinctly defined, and produce venules in 
regular order on both sides, so that the fascicles have a 
feather-like appearance (121). 
Badiate when the veins spread out from a definite point at the 
base of the frond or segment (93). 
The simplest form of anastomosing venation is when the apices 
of the veins are combined or connected by means of a marginal 
vein (113). In the more complicated forms it is spoken of as — 
Angularly anastomosing when the venules of one vein join those of 
the next, and form an angle at their point of junction (65) ; 
when the angle is very acute the term acutely anastomosing 
is employed, or sometimes called cathedrate. 
Arcuately anastomosing when the venules of one vein join those of 
the next, and together form an arch or curve (63). 
Transversely anastomosing when the venules of one vein join those 
of the next, and together form a nearly straight line (104). 
Distantly anastomosing when the venules are parallel with the 
costa, close together, and joined at long intervals by short 
cross veinlets. 
•Compoundly anastomosing when the venules are irregularly con- 
nected in a more or less net-like manner, and have variously 
directed free or conniving veinlets in the areoles (21-28, 43). 
Beticulated when the veins, venules, and veinlets are all connected 
together in a more or less net-like manner : uniform is used 
in reference to reticulated venation when there is no apparent 
difference between the veins, venules, and veinlets (31, 55). 
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