QUARTERLY CHRONICLE. 175 



fibre," or "rod," and the "crystalline cone" are con- 

 tinuous in substance, and constitute merely divisions of 

 one and the same structure; thus, in fact, regarding the 

 entire apparatus as resembling the "rods and " cones " of 

 the vertebrate eye. As this view is opposed to that of many 

 other writers, amongst whom M. Claparede may be cited in 

 the first place, it became an object to determine the exact 

 relation between the " crystalline cone " and the " rod." 

 According to Max Schultze, its point is merely in apposition, 

 and has no organic connection with the outer end of the 

 " rod." The next point he takes up is the intimate structure 

 of the "rod" itself, which he shows to possess the same 

 laminated structure that he had discovered in the outer 

 segmxcnt of the " rods " and cones in the human and other 

 vertebrate retinas. 



The memoir also includes an interesting account of the 

 differences existing between the eyes of nocturnal and diurnal 

 insects. In the nocturnal moths, for instance, the cornea is 

 usually quite colourless, and thus is capable of transmitting 

 all the luminous rays, Avhilst in the diurnal Lepidoptera the 

 corneal facets have in most cases a yellow border, sometimes 

 very intense, so that in these cases the rays towards the 

 violet end of the spectrum must be in great measure absorbed. 

 It is to be observed also that in the diurnal Lepidoptera the 

 " crystalline cone " has itself a yellowish tint, and is im- 

 bedded in a coloured pigment, Avhilst in the nocturnal it is 

 colourless and at the same time larger, so as to be capable of 

 collecting a greater number of rays. It is curious to observe 

 the close analogy thus shown to exist between the " rods " 

 and " cones " of the retina in night- and day-flying birds, as 

 referred to in the notice of a former paper by Max Schultze, 

 given in the Journal (Vol. XV, p. 25). 



Other interesting peculiarities respecting the differences 

 between nocturnal and diurnal Lepidoptera will be found in 

 the memoir. 



'' Deuxieme Serie d'Obsei'vations Microscopiques sur la 

 Chevelure." Paris, 1868. (Extrait du Tome iii, des ' Memoires 

 de la Soc. Anthrop. de Paris.') 



A ' Second Series of Microscopic Observations on the 

 Human Hair,' by M. Pruuer-Bey, has lately appeared, with 

 five plates of figures, showing the forms of transverse sections 

 of the hair in various races of mankind, and in many cases 

 at different ages. Several of the more interesting races are 

 represented by a considerable number of individuals, so that 

 the characters of their hair have been established with great 



