Miscellaneous. 407 



BIBLIOGRAPHICAL NOTICE. 



On supposed Remains of Organisms from the Pre-Cambrian Strata of 

 Brittany. By Hermann Bauff, of Boon. With illustrative 

 cuts. 



Ueber angebliche Organismenreste u. s. w. From the ' Neues Jahr- 

 buch fur Miueralogie,' &c, 1896, Bd. i. 



The Author reviews the results arrived at by M. Cayeux in his 

 microscopic researches in these old rocks. After examining speci- 

 mens himself, Herr Banff thinks that the so-called Sponge-spicules 

 are inorganic — merely microscopic threads and granules of some 

 decomposed metallic mineral, most likely pyrites. 



He notices the extremely minute size and relatively enormous 

 number of the so-called Badiolarians. He observes that M. Cayeux 

 regards the matrix as having been crystallized from an original 

 state of Badiolarian earth ; and Bauff asks if any one could deter- 

 mine optically the isotropic nature of the delicate and thin shells 

 and skeletons in the anisotropic enveloping material. He also asks 

 why M. Cayeux holds it possible that the Radiolarian skeletons, in 

 spite of the crystallizing of the quartzose medium in which they lie, 

 could keep their original colloidal silica, whilst for his Sponge- 

 spicules he does not allow of its possible preservation. Bauff con- 

 cludes that these so-called Radiolarians and Sponge-spicules are 

 minute spherical granules of some modified metallic mineral, probably 

 pyrites, in touch or coalescence one with auother. Independent 

 corroboration of his views he finds in Dr. Hiude's remarks on some 

 similar minute bodies in the ' Quarterly Journal of the Geological 

 Society,' vol. li. p. 631. 



MISCELLANEOUS. 



Modifications produced in the Organs of Sense and of Nutrition in 

 certain Arthropods by confinement in Caves*. By M. Armand Vire. 



Nowhere does the influence of environment show itself more 

 markedly or in a moro striking manner than in caverns : the 

 absence of light and the scarcity of prey produce in animals which 

 are drawn iuto them, and succeed in acclimatizing themselves 

 therein, modifications of various kinds. 



The eye, always atrophied, is more or less so according to 

 the species and the individuals of the same species. In certain 

 Amphipod Crustaceans (Gammarus, nov. species) it presents varying 

 intermediate states between the almost normal eye, of a blood-red 

 colour and apparently still capable of perceiving certain luminous 

 sensations, and the completely depigmented eye, in which nothing- 

 is preserved beyond the extcrned primitive form. Some individuals 

 exhibit varying degrees of atrophy in one eye and the other. 



* Researches made in the Jura in 1894-SJ5 and in the physiological 

 laboratory of the Sorbonne. 



