Relation between Nucleolus and Chromosomes. 53 
of the contrary opinion. Carnoy and Lebrun (1897—1899) state their con- 
clusion concerning amphibia that the chromosomes are derived from the 
nucleoli. Their figures are very convincing on this point. Macallum (1891) 
believes that the chromosomes have a double origin in amphibia. Jordan 
(1893), basing his opinion on observations made on the ova of the newt, 
believes that the nucleolar particles do not contribute to the formation of the 
chromosomes. Lubosch (1902), in the case of the ova of Triton, states: 
“Es ist sicher, dass die in diesen Stadium (maturation) vorkommeden 
Chromosomen zum Theil nukleolaren Ursprung haben” (p. 250), thus 
agreeing substantially with Schultze. 
Holl (1893), investigating the ovum of the mouse, finds that the central 
granules of the nucleolus wander out and so become chromosomes. Sobotta 
(1895), on the other hand, holds that the chromosomes are not derived from 
the nucleoli only, but from the whole chromatic substance of the nucleus. 
According to K. Foote and E. E. Strobel (1905), the chromosomes of 
the first maturation spindle in the annelid Allobophora fetida, “ are formed 
by a gradual segregation of the chromatin, which is dispersed through the 
germinal vesicle,’ the nucleolus meanwhile persisting in its original form 
and size. The chromosomes are thus not formed at the expense of the 
nucleolus. Similar conclusions were reached by Korschelt (1895) in the 
case of the annelid Ophryotrocha, and by Wheeler (1897) for Myzostoma, 
and by Griffin (1899) for Thalassema. There seems to be almost complete 
agreement among investigators that in annelids the chromosomes are not 
derived from the nucleolus. Coe (1899) inclines to this opinion also in 
the case of Cerebratulus, as also Gathy (1900) for Tubifex and Van Beneden 
(1883) for Ascaris megalocephala. However, in the case of Chetopterus, 
according to the figures of F. Lillie (1906), the chromosomes find at least 
a partial source of origin in the nucleolus; also Vejdovsky (1888), who 
studied the ova of Rhynchelmis, and Blockman (1882), who investigated 
Neritina, incline to a nucleolar origin of the chromosomes. Both Halkin 
(1901) and Goldschmidt (1902), as a result of their study of the ova of the 
trematode Polystomum integerrimum, hold that the chromosomes are derived 
exclusively from the nucleolus. 
Results of recent observations on echinoderm eggs point to at least a par- 
tial nucleolar origin of the chromosomes in the various forms. R. Hertwig 
(1896) studied the unfecundated eggs of the sea-urchin and the starfish 
poisoned with strychnine. He states that the nucleolus vanishes within the 
nucleus as the chromosomes appear, and he holds the opinion that the 
chromosomes receive a portion of their substance—‘ notwendiger Erganzungs 
material ”—from the disappearing nucleolus. E. B. Wilson (1901) finds 
two widely different types of chromosome formation in the eggs of the 
sea-urchin (Toxopneustes variegatus) artificially fertilized by Loeb’s mag- 
nesium chloride method. The two types, however, did not coexist in the 
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