Structure and development of the apical organ in trochophores
of Spirobranchus polycerus, Phyllodoce maculata, and Phyllodocemucosa (Polychaeta).Proc.
Mortalities during the initial growth stage from fertilized egg to the hatch out of trochophore
larvae (Stage 14) varied from 43% to 86%, with no correlation to temperature.
Generally, the larval development of molluscs started with a basic stage of trochophore
and then progressively develop into lecithotrophic or planktotrophic veliger larvae, which are characterized by the formation of the velum.
Suspension feeding by marine invertebrate larvae: clearance of particles by ciliated bands of a rotifer, pluteus, and trochophore
Representatives of some phyla also share a trochophore
larval stage (e.g., some polychaetes, sipunculids, vestimentiferans, echiurans, entoprocts, and molluscs).
Most annelid larval forms, feeding or not, can be readily related to the trochophore
ground plan, which Nielsen (2001, 2004) defined as a larva bearing an apical tuft, a preoral ciliated band derived from trochoblasts (prototroch), an adoral ciliary zone, and postoral metatroch, gastrotroch, and telotroch, all of which bands consist of multiciliate cells with compound cilia.
Some correlations between indicators of reproductive and larval performance were significant (Table 2); fecundity was correlated with the number of trochophores
(r = 0.90), with the initial survival of veliger larvae (r = 0.82), and with the maximum length of larvae (r = 0.90).
These large cells are shed at metamorphosis just like the trochoblasts of planktotrophic trochophores
. Thus Carinoma has larval organs and should be classified as an indirect developer.
developed after exposure of fertilized eggs to dispersed oil (25 mg/L) or oil (100 mg/L; [F.sub.15,64] = 50.16, P < 0.0001) compared with controls (Fig.
Much of the remainder of polychaete trochophores
, including epidermal epithelium of the hyposphere, the generative zone for metameres, the gut (whether functional in the trochophore
or not), derivatives of the mesoderm, and ingressing neurons of the cerebral ganglia, continue to develop during larval, metamorphic, and juvenile development as components of the definitive adult body (e.g., Seaver et al., 2005; Kulakova et al., 2007).
1999); the D-larvae, trochophores
, eggs, and sperm of C.
Thus at least some palaeonemertean larvae appear to be modified trochophores
. directly comparable to the trochophore
larvae of other spiralians.