EE CENT KESEAECHES IN MINUTE LIFE. 
251 
parent form. The observers were rewarded for their most patient 
watching by seeing at last the sexual reproduction of these 
creatures. Two coalesced in a rounded mass and burst, pouring 
out a swarm of minute spores, as described in other cases. 
Strange as it may seem, the fish maceration afforded another 
remarkable and elegant monad, which its discoverers term, from 
its shape, the calycine monad. This is shown in fig. 14, and ex- 
hibits a considerable complication of structure. Like other 
monads this multiplies by fission, becoming first partly amoeboid, 
but it also proceeds by sexual union. Fig. 15 shows two of 
them, which have assumed a conical amoeboid condition, uniting 
themselves together. When this process is complete they make 
a sort of plum-shaped sarcode mass, in a sac with a few corners, 
but nothing like the curious amoeboid form. This sac becomes 
round and smooth, then bursts, discharging swarms of extremely 
minute germs. When these germs begin to develop, they look 
about from a fiftieth to a twentieth of an inch long when mag- 
nified 5,000 times linear measure, and they gradually take the 
parent form. 
In the preceding account of Messrs. Dallinger and Drysdales 
researches a great many matters of interest have been omitted, 
and for such details the reader is referred to the series of their 
papers in the “Monthly Microscopical Journal,” 1873-5. One 
very curious and common feature was the possession by the 
monads of an “ eye spot,” which opened and shut in a snapping 
manner. Exactly what this organ was could not be discovered ; 
but its presence, together with that of a nucleus, suggests a more 
highly organised condition than was previously known in such 
minute organisms. The facts here cited show that monads of 
excessively small size, after multiplication for an indefinite 
number of generations by fission, resort to a sexual process, that 
their germs resulting therefrom are so minute as to be invisible 
except in a mass with the highest and best objectives at present 
made, and that the life series of the same creature comprehends 
forms so different that they would be referred to different species, 
or in some cases to different genera, or even families, if the 
order of their succession had not been made out. 
The germs or spores of these creatures resisted very high 
temperatures; those of the cerco-monads 260° F. (178° C.). 
The “ springing monad,” as its discoverers call the one that 
anchored and behaved somewhat like vorticella, and made a 
multiple fission, did not emit the cloud of minute sporules, and 
was destroyed by less heat. No adult form withstood a high 
temperature, but as great a heat as 300° F. did not destroy the 
minute sporules of the uniflagellate form. The biflagellate 
germs survived 250° F. 
After these remarks it is impossible to admit that simple 
