Stereospecific triglyceride analyses were performed on fats of the following animals: five aquatic invertebrates, five freshwater fish, six marine fish, three marine birds, two amphibia, two seals, a whale, and a marine turtle. The distribution of faty acids was asymmetrical in most cases. A formula is presented which describes the general tendencies of fatty acid distribution in many animal fats, and some special rules which modify this formula are stated.

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The seasonal variations in lipid content and general "condition" of cod, Gadus morhua L., from an inshore population have been determined.Four female and four male fish were chosen from 20 live cod brought in monthly from Terence Bay, Halifax County, Nova Scotia, the fish were pooled and the lipid content determined on the flesh, livers, and gonads. The flesh lipids varied from 0.57% to 0.74% and the oil content of the livers from 15% to 75%.The general "condition" of the fish as expressed by [Formula: see text], the liver condition by [Formula: see text], and the fat content of the liver all showed seasonal variation with maxima in the fall and minima in the spring. KF varied from 0.79 to 1.05 and KL from 1.0 to 4.5. No seasonal variation in the amount of flesh lipids could be detected.

Gastric juice of lobster hydrolyzed the following substrates: triolein (enzymic activity: lipase), tributyrin ("lipase"), Azocoll(R) (proteinase), TAME and BAEE ("trypsin"), ATEE ("chymotrypsin"), HPLA ("carboxypeptidase A"), DNA (deoxyribonuclease), RNA (ribonuclease), p-nitrophenyl-phosphate (phosphatase), and p-nitrophenyl-N-acetyl-β-glucosaminide (chitobiase). (The quotation marks signify that the substrate specificities are typical of the quoted enzymes of mammalian or microbial origin. The spectra of specificities, however, of these enzymes and the corresponding enzymes of lobster are not necessarily identical.) Very low activities were found against RBB-starch (amylase) p-nitro-phenyl-α-(and β)-glucopyranoside(α- and β-glucosidase), p-nitrophenyl-β-galactopyranoside (β-galactosidase), and chitin azure (chitinase). No activities corresponding to phospholipase (lecithin), carboxypeptidase B (benzoylglycyl-L-arginine), elastase, glycylglycine dipeptidase, or leucine aminopeptidase were found.Gel filtration of gastric juice proteins on Sephadex(R) G-100 yielded estimates of molecular weights, among them: chitobiase 100,000; phosphatase 80,000; lipase 43,000; DNase 33,000; "trypsin" and ribonuclease 25,000; and two proteinases with optima around pH 4 and 8 and the low molecular weight of 12,500; proteolytic activity at pH 4 was also associated with the molecular weights 25,000 and 50,000.In ion-exchange chromatography, enzymes were eluted from DEAE-cellulose in the following sequence of increasing anionic character: chitobiase, proteinase (pH 4), proteinase (pH 8), lipase, "carboxypeptidase A," DNase, phosphatase, and "trypsin" and "chymotrypsin."Of the principal enzymes, only one (chitobiase) had its optimum at the pH 5 normal for lobster gastric juice. The lipase had an optimal pH around 7, phosphatase near 9, and "trypsin" near 8; proteolytic activity shows a maximum at pH 7–8 and another maximum, unusual for Crustacea, at pH 4.Much of the protein of gastric juice could not be connected with any enzymic activity. The proportion of nonactive protein seemed to increase with starvation of the animals. We found no evidence for the occurrence of zymogens.

Analysis of the fatty acid composition of a marine diatom, Skeletonema costatum, shows that the longer-chain highly unsaturated fatty acids characteristic of fish lipids can be produced by some phytoplankton as well as through intermediary zooplankton. Comparison of cultures of various degrees of maturity indicates that the fatty acid composition of mature cultures in laboratory experiments is not necessarily typical of pelagic diatoms. The origin of atypical C16-polyunsaturated fatty acids is discussed.