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I I I I I I I I I I I I I I I I I I I - 107 - Thick plates were commonly observed to have multi-layered fZ:I'owth. These layers were of varying shapes and sizes. The layers consisted of hexagonal plates, often with ribs, small stellar germs, sectors and other features. Often these dissimilar layers were all part of one crystal. Seldom did thick plates have frozen drops at their center in spite of the double and multi- layered growth commonly present. Ribs were not observed on thick plates less than about 300 lJm in diameter. The shapes of the plates were often odd and irregular. The irregularities and peculiarities in the shape of the crystal appeared to be accentuated near the transition temperature of -IOoC.V-shaped notches were commonly found in the largest two sides of these irregularly shaped crystals. Aircraft observations indicated that riming was seldom present on these crystals. Thick plates were larger than plain plates and ranged in diameter from about 300 lJm to over 1000 lJm with an average diameter of about 555 lJm. Thick plates were not observed to break up in the air. 4.2.6 Star-like Crystals (PIb, PIc, Pld, PIe, Plf) Our aircraft observations confirmed the conclusion of Magono and Lee (l966) that star-like crystals grow between about -l2 to -l70C in both water saturated and sub-water saturated conditions. In the air, star-like crystals were generally observed as individual crystals, although these crystals interlaced with other star-like crystals and as part of aggregates were not uncommon. Ground observations indicated that most star-like cryr;tals occurred as parts of aggregates and often these aggregates consisted entirely of star- like crystals.