1917.] The Fourth Indian Science Congress. clxxxiii 



mud in suspension, (2) influx of putrid water from rivers into the sea. 

 None of these theories can be regarded as satisfactory. The result of 

 certain investigations made on the west coast shows that the mortality 

 is to be directly traced to the immense development of Euglenid swarms 

 in inshore waters after the rains. The water at this time is highly 

 charged with dissolved organic matter and thus favours the growth and 

 multiplication of Euglenids. The effect of the vast superabundance of 

 Euglenids is to render the water thus contaminated unsuitable for the 

 existence of all kinds of fishes, crustaceans, and molluscs. Many of 

 these animals are thrown ashore moribund or dead ; great quantities of 

 them are stupefied and die and putrify in the sea. The foul water thus 

 produced extends seawards under favourable conditions and thus spreads 

 the area of the plague and causes further mortality among fishes. The 

 Euglenid concerned differs from typical fresh-water Euglenids. The 

 author gives details of its structure and behaviour. 



A method of cutting sections of the wings of Insects.— By 



E. H. Hankin. 



The wing is first placed in a solution containing ammoniacal silver 

 nitrate, Rochelle salt, and alcohol. After a time varying from a few minutes 

 to a few hours the wing is thereby blackened owing to the deposit of a thin 

 film of metallic silver. The wing is then washed in 50% alcohol and placed 

 in rectified spirit. It is then embedded in jelly. The jelly used is a strong 

 agaragar containing eight per cent of hyposulphite of soda. The portion 

 of the°lump of jelly containing the wing is cut into ten slices of equal 

 thickness by means of a Gillette razor blade. The slices are threaded on 

 to a wire in the right order after trimming to a convenient size. They 

 are then placed in a half per cent solution of tartaric acid m 70 per cent 

 glycerine for 24 hours. The acid causes precipitation of finely divided 

 sulphur (by decomposition of the hypo) in the jelly which is thereby 

 rendered white and opaque. The sections therefore are seen in black on 

 a white background. The sections are mounted in a cell containing gela- 

 tine jelly. , , . „,. 



A number of wings of different kinds of insects treated in this way 



were exhibited. 



Anthropological notes on the Eurasians of Indo-Portuguese 

 descent in Cochin— By L. K. Anantakrisiiva Iyer. 



Introduction.-Orimn and History of the Community. Habitat .-In- 

 termarriage of the Portuguese with native women m former times. 

 Marriage customs. -In former times and at present. Inheritance - 

 Religion. Funeral customs. Occupation. Dress, appearance, d*c. Ine 

 paper was illustrated with lantern-shdes. 



— By C. R. Narayan Rao. 



.1/ 



ornata (rsom.j. — ny ^- **• «»«»*»» 



' The striking feature in the colouration of the larva ol Mycrohyla 

 ornaLl J Mollis the occurrence of a bright *°^7^<ft, 

 band and of silver brilliance on the s,des and the ventral surface of the 

 abdomen, and probably used as a warning ^vertsement in consequence 

 of the floating habits of the tadpoles The dorsal b»d formed of very 

 fine plates of guamn or iridocytes while the silver brightness i .due to^ the 

 reflecting tissue or argenteum, which is notguanm kalk On chenucal 



analysisf it is found that the substance °V? ^?f S^^ 

 identica with that met with in the .r.descent tissues of fishes. . 



The only organ that bears both chromatophores and indocjtes 







