70 The Vegetable Individual in its relation to Species. 
or, different nurses may nourish the two sexes so that a division 
of generation will occur even at the degree of nurse-formation. 
If in the last case the nurses are not single ones, but even then 
form per se a family stock, then on the same stock we may either 
have male-bearing and female-bearing nurses together, or these 
two kinds of nurses may be divided among different stocks, ac- 
cording as the division of generation occurs in a determinate 
later generation, or is present already in the first. Although as 
yet the observations of these relations by no means form an une 
broken chain,* still this much is certain, that in avimals, in the 
same Way as in plants, both moneecious and deecious forms ‘occur; 
and hence there are families partly bisexual, -partly unisexual. 
Coryne, Tubularia, Campanularia, and probably all Sertula- 
rie (hence, doubtless, the greater part of Hydroids), also Vere- 
titlum, Cynomorium, accor rding to Steenstrup, Krohn and other 
observers, are dicecious,—whether they form small simple stocks 
as Coryne squamaia, or smail ramified trees, as Syncoryn@, 
Campanulare,t etc. On the other ‘hand Siphonaphorie, ace 
cording to Milne Edwards’ description of Stephanomiat (and 
judging from Sars’ description of Agalmopsis), are moncecious 
family stocks; Hydre are also monecions.§ ‘To enter any fur- 
- 
ther into these relatious as they occur in the lower animals wou uld o 
lead us too far from our subject; but it may be in place to give oO 
some details as to the manifold relations under aster mel S a 5: 
branches, or ouly unessential ones,—when, therefore, as it is usti- 
ally expressed, it is uniaxial,” as e. g., in Rubus, Chumamorus, — 
Lychnis, and Viscum. Much more frequently, however, divis- 
ion of the sexes occurs in plants which at the same time have a 
eyclical succession of shoots (alternation of generation ),—a suc- 
cession which each of the two heterogeneous stocks passes 
through independently, ay sp always part passu. This is @ 
circumstance which must not be neglected in considering the 
fercend oad of habitus in ‘aala: oe female flowers. Thus, in Afer- 
* Thus e g., as far as I know, it remains to be — whether the single 
of Medusae produce Medusee of both sexes, or, as is ey only those wes 
en ee In Aphis ee still needs ie betes hy 
ermined, 
+ A en 5 Hermaph., pp. 6 
Ann, des Se. Nat., 1841, p. 21 Shain 
he later investigations into Siphonophoria by cabaggs bcd Phil. Journ, 
1852, Rai Zeitschr. as SS ee pao eroem L. Unters a lees 
rate 
