holoblastic


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holoblastic

[¦häl·ə¦blas·tik]
(embryology)
Pertaining to eggs that undergo total cleavage due to the absence of a mass of yolk.
References in periodicals archive ?
Opisthobranch embryology involves spiral, typically holoblastic, cleavage, which is highly conserved within annelids, molluscs, and nemerteans (Wilson, 1892; Casteel, 1904; Thompson, 1958; Maslakova et al.
scaura: (1) transition from holoblastic cleavage to superficial cleavage, (2) germdisc condensation, (3) germband formation and elongation, (4) germband flexure and limb bud formation, (5) limb bud elongation and segmentation, and (6) dorsal closure and reversal of cephalic direction.
The early holoblastic cleavages are diagrammed in Fig.
Owenia collaris embryos undergo holoblastic spiral cleavage to form a coeloblastula, which, although exceptionally hollow (again like some nemerteans), conforms to the ancestral pattern for annelids (Okada, 1970).
pentagona through the stages of holoblastic radial cleavage, early blastula, wrinkled blastula, and gastrula was typical of development in lecithotrophic sea stars (Byrne, 1995).
The zygote then undergoes radial, holoblastic cleavage and forms a hollow coeloblastula.
Although microtubules have been correlated with cytoplasmic movements that follow fertilization in amphibians (4), ascidians (5), and annelids (6), these embryos do not form blastodisc caps and, unlike the squid, they undergo complete or holoblastic cleavage.