REPRODUCTION, SEX, AND HEREDITY. Gen. >5 'ub. 51 
Hermaphroditism: Describes in Ophryotrocha the formation of both 
ova and spermatozoa in the same organ at the same time. Besides her- 
maphrodite and unisexual forms, ho found apparent females with male 
cells as well as ovaries, and apparent males with ova as well as sperms ; 
Korsciielt (297). — In insects ; Vosseler (518). 
Parthenogenesis, &c. ; Vonhof (517). 
Hybridism : Cyprinoids ; Heincke (226), Morgan (363). — Believes he 
has fertilised the ova of Asterias with the sperm of Arbacia ; Lataste 
(308), Suciietet (499). — Two fertile Cyprinoid hybrids; Knauthe 
(287). — Study of a hybrid between a fertile mule and horse ; Cornevin 
& Lesbre (109). — Hybridism among insects : Pairing or attempted 
pairing between different species is common. Hybrid offspring, how- 
ever, are only known among Lepidoptera. Most are sterile. The hybrid 
has usually some characteristics of both species, but the external features 
of the hybrid are usually much more like those of the paternal species 
than those of the maternal species ; Standfuss (488). 
b. Heredity. 
Calderwood (85), Haacke (202), Koehler (293), Lataste (307), 
Mann (335), Nussbaum (380), Orr (382), Waldeyer (521), Weis- 
mann (536). 
A theory of development and heredity : Germ-cells not isolated, e g. t 
from nervous influences. No essential difference between development 
and reproduction of Protozoa and those of Metazoa. Inheritance of 
acquired characters in both. Epigenetic theory of development ; the 
forces of the environment mould the growing organism. Great import- 
ance attached to direct mechanical effect of the environment ; Orr (382). 
Historical notes on the idea of the continuity of th6 germ plasm ; 
Baur (32), Nussbaum (380), Weismann (537). 
General work on normal and pathological inheritance ; Sanson (450). 
The theories of Weismann ; Del age (126), Haacke (202), Hartog 
(215), Morgan (361), Romanes (429, 430), Spencer (483, 484). 
Some laws of heredity ; Buckman (77). 
Recapitulation theory in biology ; Buckman (78). 
Hymenoptera, heredity in the social colonies of : Embryological and 
palaeontological evidence negative the idea that the various types in the 
colony are produced by the treatment accorded to the young by the 
workers, each generation for itself. “It is more probable that the basis 
of the entire community, the original fertile soldier, acquired his charac- 
ters in the usual way, by use, and that all other forms have been derived 
from him by inheritance, modified by disuse and degeneracy, under the 
influence of variations in the food supply ; Cope (106). 
Telegony, citation of facts ; Finn (159). 
Heredity versus Evolution ; Gilman (183). 
Theory of Gemmaria ; Haacke (202, 205). 
Atavism, &c. ; Mann (335). 
