ZOOLOGY AND BOTANY, MICROSCOPY, ETC 741 



Eye of Protopterus.*— E. Grynfeltt gives an account of the minute 

 structure of the eye of Protopterus annectens, which he finds on the 

 whole to be nearest that of other fishes, especially as regards the external 

 and the middle tunic. On the other hand, as regards the retina, there 

 is an approximation to the Urodelous Amphibian type, perhaps by con- 

 vergence, especially as regards the details of the rods and cones. 



Distribution of the Muscle-fibres in Heart of Fishes. | — Luigi 

 Sala has examined the heart in ten Selachians, two Ganoids, and fifty-six 

 Teleosteans in reference to the arrangement of the muscle-fibres. He 

 describes various dispositions, e.g. the occurrence of longitudinal bundles 

 to the inside, transverse bundles to the outside, and radial bundles 

 between. 



Cutaneous Papillae in Gobius.J — L. Sanzo has made a study of the 

 cutaneous papillae, or cyathiform organs, which occur in various series — 

 about the orbit, the jaws, the operculum, the back, the sides, etc. — of 

 the various species of Gobius, seventeen of which are dealt with. He 

 describes the distribution of the papilla? characteristic of the different 

 species. 



c. General. 



Animal Life of Sea-bottom.§ — C. Gr. Joh. Petersen and P. Boysen 

 Jensen have studied the quantity, composition and nutrition of the 

 bottom-fauna in Danish fjords. The stomachs of bottom-animals 

 chiefly contain a " dust-fine mass." This is partly inorganic, partly 

 organic, but with few living organisms. It is largely due to the 

 benthos vegetation, especially in the thin brown layer which is upper- 

 most. In several enclosed fjords with rich bottom-vegetation, large 

 quantities of dissolved organic matter have been found in the sea-water. 

 Most of the bottom-animals feed on detritus, partly obtained from the 

 water, partly from the brown layer. The authors emphasize the import- 

 ance of quantitative studies. 



Validity of some forms of Mimicry.|| — N. Manders has devoted 

 much attention to the insectivorous birds and reptiles in Bourbon, 

 Mauritius, and Ceylon in their relation to alleged cases of mimicry. He 

 has reached the following conclusions : 



In Bourbon and Mauritius there are no butterfly-eating birds or 

 reptiles, so that cases of mimicry occurring there cannot be due to their 

 influence. In Ceylon it has been shown that the butterfly-eating reptiles 

 are impartial feeders. 



A trained observer can distinguish the majority of these mimetic 

 butterflies at a distance of twenty or thirty feet, and frequently at the 

 same number of yards. This being so, it is certain that a bird, which 

 depends on its powers of observation, could soon learn to discriminate 



Drongos feed largely on Euplceas, and this being so, a Papilio 



* Bull. Mens. Acad. Sci. Montpellier (1911) pp. 210-32 (1 fig.). 



t Rend. R. 1st. Lombardo, xliii. (1910) pp. 825-9. 



X MT. Zool. Stat. Neapel, xx. (1911) pp. 251-328 (4 pis. and 15 figs.). 



§ Report Danish Biol. Station, xx. (1911) pp. 1-78 (6 pis., 3 charts, and 6 tables) . 



H Proc. Zool. Soc. (1911) pt. 3, pp. 696-749. 



