Prof. Owen on Life and Species. 59 
infusions, answers to the molecular contents of the ovisac. In 
both instances the molecules or granules aggregate into groups 
forming spheroids more opake than the rest (as in fig. 555, A): 
as the aggregation and coalescence advances the sphere becomes 
more opake, more definite: then a clear line marks its inclu- 
sion within a membrane, analogous to a ‘zona pellucida,’ and 
proclaims its individualization (as in ib. B). 
ext appears a clear nucleus, answering to the germinal 
vesicle (as in ib. c). Fission of the nucleus is followed by that 
of the monad, which may thus multiply itself within the pri- 
mary envelope (Chlamydomonas, ccoxuix, fig. 29), like the 
cleavage-formation of the germ-mass: ciliary organs are ac- 
quired in both instances, rotating the germ-mass in the mam- 
malian ovum, and extricating the monad from its proligerous 
bed ; whereupon it revolves or darts along, a free animalcule, 
in the subjacent liquor of the infusion. 
In neither instance is there any support, from observation, 
ofthe derivation of germ-mass or of monad by evolution out 
of a pre-existing cell: in both instances have the processes of 
— or building up ab initio been repeatedly seen and 
ced. * 
sion a slightly opalescent appearance precedes the formation of 
the thin superficial film. This consists of molecules of various. 
inclosed in ‘ goldbeater’s’ skin or other close membrane, and 
Inserted beneath the integument of a living Mammal—even 
faction by endosmosis—shows its results in the form of gran- 
Ke Ame, 
enclosing bag} In the proligerous pellicle the larger molecules = 
unite end to end, forming bacteriums, or less regularly into 
_ * ovcx’’, pp. 352-388. cocxt”, pp.133-253. ccoxm’’, pp. 121-129. cccxmr”’, 
ip. 1046, Aik sth p. 974. cocxv”’, p. 467: Mantegazza ‘spent sixteen consecu- 
2 _ tive hours in observing this genesis. os ek pe © Se 
+ coxvr’ 
