New three-component liquid crystal systems creating spontaneously nematoid-type filaments at the transition from the isotropic melt and formation of the nematoid-type filaments at the nematic - smectic A transition in dilute solutions of smectogen in silicon oil are reported. We have observed over 50 new three-component systems, composed of smectogen, nematogen and chiral dopant, in which the formation of the nematoids occurs. The plate-type nucleation of the mesomorphic phases has been observed at the transition from the isotropic melt for pure smectogens and also for three-component systems. In addition, creation of the nematoid-type filaments in dilute solutions of mesogen (NPOOB) in silicon oil has been observed here. Early stages of the plate-type nucleation have been examined using Nomarski contrast. The refractive profiles of the filaments have been examined using double-refracting microinterferometers.