The Journal of experimental zoology . Fig. dianthus. Larvae. Stages of transformation from free-swimming to sedentary views. A—Free-swimming larva. Age, 9 days. Shows long apical cilium (X208). B—Swimming but sluggish larva. Age, 9. days. Shows setae and shortened apical cilium (X185).C—^Attached larva (X90). Age, 17 days. Three pairs of head lobes. Beginning of secretion oftube. D—^Age, 17 days (X90). E—Age, 16 days (X85). F—Age, 17 days. Second of originalthree pairs of branchiae shows secondary branches ( X 70). Compensatory Regulation. 43. //-/ In Fig. I OF, also 1
The Journal of experimental zoology . Fig. dianthus. Larvae. Stages of transformation from free-swimming to sedentary views. A—Free-swimming larva. Age, 9 days. Shows long apical cilium (X208). B—Swimming but sluggish larva. Age, 9. days. Shows setae and shortened apical cilium (X185).C—^Attached larva (X90). Age, 17 days. Three pairs of head lobes. Beginning of secretion oftube. D—^Age, 17 days (X90). E—Age, 16 days (X85). F—Age, 17 days. Second of originalthree pairs of branchiae shows secondary branches ( X 70). Compensatory Regulation. 43. //-/ In Fig. I OF, also 17 days after fertilization, we find a stage con-siderably more advanced in which each of the middle branchiae hasalready sent out three branches, which may / be labeled accordingto age, II—I, II—2and II—3. Of these itwill be seen that II—ivery early takes onthe character of oneof the main branchialtrunks, so that we thusget a stage with fourpairs of —2 and II—3 retainthe characters of pin-nules of the Branchia II. Neither I nor IIIhas any branches atthis stage. Fig. iiA shows alater stage taken fromthe same dish at thesame time (17 days).Here we still haveno branches of I and III. Branchia II hasfive branches and thefirst branch of L-II(L-II—i) a branchletof itsown (L-II—I—i)just appearing as avery small knob. Itis very evident thatBranchia II is rapidlyoutgrowing I and IIIin strength. Fig. I IB (19 days old) gives a still older stage.^Branchia I oneach side has not increased much in size and is hardly larger than
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Keywords: ., bookauthorwi, bookcentury1900, bookdecade1900, booksubjectzoology
