Abstract
The three cuticles of the egg—maternal, serosal, and embryonic cuticles—are basically similar, and two primary layers may be distinguished in each of them. These layers, which correspond to the principal layers of typical post embryonic cuticle, are called epicuticle and endocuticle. The new term maternal cuticle is to be preferred to the old term "chorion". Chromatographic analysis of hydrolyzates of the cuticles has shown the following amino acids to be present in each of them: alanine, aspartic acid, glutamic acid, glycine, serine, cystine(eine), threonine, lysine, histidine, arginine, proline, valine, leucine(s). Tyrosine and phenylalanine are present in the serosal and embryonic cuticles, but are absent from or present only in traces in the maternal cuticle. Tryptophan is present in the maternal and embryonic cuticles, but absent from the serosal endocuticle. Glucosamine was found in acid hydrolyzates of the serosal and embryonic cuticles, adding confirmatory evidence for the presence of chitin demonstrable by the chitosan test of Campbell. Positive Liebermann–Burchardt tests are given by chloroform extracts of the embryonic cuticle and of the vacated shell. These findings are discussed in relation to the function of the cuticles.
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