The stimulus provided to cercariae by the skin fat of their definitive hosts is not the same for Schistosoma mansoni and Austrobilharzia terrigalensis. Cercariae of the former parasite are stimulated by unsaturated fatty acids, those of the latter by cholesterol.

A reinvestigation of the penetration stimulant factors present in crude egg lecithin, which contains both cholesterol and free fatty acids as impurities, has shown that the latter are responsible for the stimulus in S. mansoni. The phospholipid fraction is inactive as is pure cholesterol. A little excitation of cercariae is produced by the monoglyceride fraction. These results fully confirm earlier findings.

Of surface active agents other than lecithin, stimulatory activity was found only in one product which possessed carboxyl groups. Of the C18 acids examined, stearic (18:0) is inactive, oleic (18:1) slightly active, linoleic (18:2) and linolenic (18:3) acids highly active. Oleic acid was shown by GC-mass spectrometry to be the most abundant acid in crude egg lecithin and is probably the main penetration stimulus present.

Ward, P. F. V. The metabolism of glucose by Haemonchus contortus, in vitro.

Page 184, two lines from foot of page. For ‘glucose and on worms’ read ‘glucose and no worms’.

Lainson, R., Landau, Iréne and Shaw, J. J. (1974). Observations on nonpigmented haemosporidia of Brazilian lizards, including a new species of Saurocytozoon in Mabuya mabouya (Scincidae).

Due to postal delay in the receipt of corrected proofs of the above paper, the following errors have regrettably appeared in its publication and should be corrected as follows:

Page 215, lines 3 and 4 of the Summary, and page 216, line 10. The text should read ‘ …Garnia morula (Telford, 1970) Lainson, Landau & Shaw, 1971;… ’ and not ‘ …Garnia (Plasmodium) morula (Telford, 1970), Lainson, Landau & Shaw, 1971;…’

Page 220, lines 24 and 25 of the text should read ‘…Plasmodium tropiduri, P. diploglossi, a Plasmodium species close to P. diminutivum Telford 1973 a and Saurocytozoon’. Not ‘…P. diploglossi (a parasite close to P. diminutivum Telford 1973a) and Saurocytozoon’