sex ANf) REPKobucTioN. Gen. Sub. 25 
forms which are either exogamous or sexually differentiated. Here the 
nuclei which fuse to remove the reproductive incapacity must be of 
distinct origin. Exogamy of isogametes is merely the expression of 
karyogamic incompatibility of close blood relations. The constitutional 
weakness of the later terms of a cycle of fissions is largely due to the 
continuance of the association of nucleus and cytoplast unchanged. The 
evil effects of the prolonged association are probably due (a) to the 
nucleus responding less actively to the stimuli from the cytoplasm ; (6) 
its consequently inadequate directive power ; (c) the resulting bad per- 
formance of its work by the cytoplast ; ( d ) the imperfect nutrition of 
the nucleus ; (e) the failure of the cell as an organic whole. Replacement 
theories of fertilisation fail to account for one or more of the following 
facts : — {a) multiple isogamy ; (5) the non-discrimination of the broods 
of exo-isogametes into two categories, of which the members of either 
would pair with those of the other category, but not of their own ; (c) 
the absence of “ excretion phenomena ” of any kind in so many cases of 
gametogeny ; (d) the existence of true parthenogenesis of male as well as 
female gametes ; ( e ) the formation of a male individual from the ex- 
clusively female oosphere of the hive-bee. 
Heape, W. Preliminary note on the transplantation and growth of 
Mammalian ova within a uterine foster-mother. P. R. Soc. xlviii, 
pp. 457 & 458. 
Two ova from an Angora doe rabbit (fertilized thirty- two hours pre* 
viously by an Angora buck) were transferred into the upper end of the 
Fallopian tube of a Belgian doe rabbit, which had been fertilized three 
hours before by a buck of her own breed. When the Belgian doe gavo 
birth, four young were Belgian, two Angoras. 
IschiEawa, C. Vorliiufige Mittheilungen fiber die Conjugationserschei- 
nungen bei den Noctiluceen. Zool. Anz. xiv, pp. 12-14, 4 figs, 
In conjugating the two cells become one, The nuclei do not fuse, but 
remain lying apposed. Division of both takes place so that half of each 
nucleus passes into each of the two resulting portions. 
. On the formation of Eggs in the Testis of Gebia major, De Haart. 
T. c. pp. 70-72, 2 figs. 
The testis of Gebia major (20 males with secondary sexual characters) 
produces ova posteriorly. The ova do not pass out, 
Knatz, L. Ueber Enstehung und Ursache der Flfigelmangel bei 
den Weibchen vieler Lepidopteren. Arch. f. Nat. lvii, pp. 49-74, 
1 pi. 
There are 183 cases of female Lepidoplera With reduced or absent 
wings. 
* Knauthe, K-. Zur Biologic dcr Fisohe. Zool. Anz, xir, pp. 73-7(1. 
