164 SUMMARY OF CURRENT RESEARCHES RELATING TO 



second month as a hollow, somewhat funnel-shaped tube from the 

 future cavitas conchae. From this primary auditory meatus there arises, 

 in the beginning of the third mouth, an epithelial plate, the lamina 

 epithelialis meatus. This becomes differentiated into a tympanic and a 

 non-tympanic part, and in the seventh month splits into two layers. 

 The cavity so produced forms the final or secondary meatus, the primary 

 one corresponding chiefly to the cartilaginous part of the permanent 

 structure. The bony and cartilaginous parts of the meatus differ from 

 one another as regards their epithelial lining, that of the former region 

 being without hairs and glands, while the latter possesses these. From 

 the time of the first appearance of the primary auditory meatus its 

 inner end is evaginated in the form of a rounded projection, the tuber- 

 culum membranae tympani, which ultimately forms the membrana propria 

 of the tympanic membrane. 



Development of Iris in Man.* — A. Szili gives a preliminary account 

 of his researches on this subject. The most important point shown by 

 his preparations is that in man the musculus sphincter iridis is an epi- 

 thelial muscle, and arises at the beginning of the fourth month out of 

 the epithelial cells at the line of junction of the outer and inner layers 

 of cells in the secondary optic vesicle. 



Alleged Case of Transmission of Acquired Characters.-]- — Prof. W. 

 Leche describes the thick, horny, hairless callosities on the carpals of 

 Phacochcerus africanus, and interprets them as directly induced by the 

 way in which these hogs rout about for roots and tubers. They get 

 down on their knees (carpal-joints) and press forwards as they dig with 

 their upper canines. The fact that the callosities are distinctly seen in 

 the embryos leads the author to conclude that we have here to do with a 

 case of the transmission of an acquired character. [It is, however, an 

 unproved assumption that the callosities were, to begin with, somatic 

 modifications.] Leche also refers to the molars of the dugong, which 

 have tubercles in the embryo that undergo apical absorption and become 

 flat before any chewing has begun. 



Copulation of Bats.J — G. Salvi describes his observations on the 

 bats inhabiting the " grotta dell' Inferno," near Sassari, and shows, if 

 we rightly understand his point, that copulation often occurs in spring, 

 though the autumnal pairing is undoubted. Out of 479 individuals, 

 341 were males and 138 were females, and there seemed clear evidence 

 of vernal sexual union. 



Olfactory Organ in Vertebrates.§ — Prof. H. Strasser, following 

 His, points out how much the characteristic appearance of the different 

 vertebrates depends upon the degree of development of the structures 

 related to the olfactory organ, and discusses the significance of the 

 great development of these parts in the higher vertebrates. In the 

 first place, he rejects the idea that the complex nature of the skeleton 

 of the nose in e.g. mammals, is to be ascribed to the needs of the olfac- 

 tory organ itself, and also doubts the validity of the suggestion that this 



* Anat. Anzeig.. xx. (1902) pp. 161-75 (6 fig3.). 



t Biol. Central^., xxii. (1902) pp. 79-82 (1 tig.). 



J Atti Soc. Sri. Nat., xiii. (1902) pp. 289-41. 



§ Arch. Sci. Phvs. Nat. Geneve, xii. (1901) pp. 609-22. 



