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larvae. Thus the larvae of Dalmanites and Proctus, with their prominent 
eyes, and glabella distinctly terminated and rounded in front, have char- 
acters which do not appear in the larval stages of ancient genera, but 
which may appear in their adult stages. Evidently such modifications 
have been acquired by the action of the law of earlier inheritance or 
tachygenesis.” 
Bryozoa.—My studies (17, 18) were the first to show that there is in 
the bryozoan colony a definite recapitulation of ancestral characters, and 
that in this particular the colony behaves as an individual. This same 
fact was very clearly pointed out by Ruedemann (47) two years earlier 
in the Graptolites, and I take pleasure in quoting his very explicit state- 
ment. He says: “Furthermore the fact that the thecze within the same 
colony show a gradation from phylogenetically older to younger forms, 
and therefore analogous to the organ of a growing individual, pass 
through ancestral stages, as, e. g. do the septa of a cephalopod shell, 
demonstrates how closely the zooids of this colony were united into one 
organism, and that practically they were more the organs of an individ- 
ual than the component of a colony. . . . . If the graptolites so 
closely approached the morphologic value of an individual, it may be ex- 
pected that, like an individual, the whole colony has its ontogeny and re- 
passed ancestral stages.” 
My studies, referred to above, brought out the fact that the bryozoan 
colony begins as a minute hemispherical body, the “protcecium” which is - 
the earliest exoskeletal stage of the first. individual of the colony. This 
protecium (basal disc) is very conspicuous in the Cyclostomata, and also 
in the ancient Cryptostomata (as shown in /’enestella).. It can not be 
definitely asserted that the protescium corresponds to any ancestral bryo- 
zoan, but the marked resemblance of the zowmcia of some of the ancient 
Stomatopora of the Ordovician to the protcecium is at least very sug- 
gestive. 
The ancestrula, or first complete individual ef the colony, has long 
been known to present characters more similar to those of ancestral forms 
i] first used the term protecium as the designation of the first individual of 
the colony, and in this sense it would be exactly equivalent to the term anczestrula 
of Jullien. In a later paner (18) I restricted the term to the basal disc (of 
Barrois) which is the calicified wall of the metamorphosed and histolyzed embryo 
in its earliest sedentary stage. Out of this basal dise the first normal individual 
arises by a process stirctly analogous to budding. In this sense, therefore, the 
term protecium is exactly correlative with the terms protegulum, protoconch, 
prodissoconch, etc. 
